Photo: John Stillwell - WPA/Getty

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge kiss on the balcony of Buckingham Palace after getting married on April 29, 2011 in London, England.

01of 20March 2006Prince William and Kate Middleton.Indigo/GettyPrince WilliamandKate Middletonmet while they were both students at the University of St. Andrews in Scotland. Shortly after their 2005 graduation, Kate cheered William on at sporting event at Eton College, where they were spotted with their arms around each other.

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March 2006

Prince William and Kate Middleton.Indigo/Getty

Prince William kisses Kate Middleton, after playing the Field Game in an old boys match at Eton College on March 18, 2006 in Eton, England.

Prince WilliamandKate Middletonmet while they were both students at the University of St. Andrews in Scotland. Shortly after their 2005 graduation, Kate cheered William on at sporting event at Eton College, where they were spotted with their arms around each other.

02of 20November 2010Kate Middleton and Prince William on the day of their engagement announcement.Chris Jackson/GettyThey’re engaged!Prince William and Kate announced their engagementwith a smiley photo call at St. James Palace, where they posed with their arms linked.

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November 2010

Kate Middleton and Prince William on the day of their engagement announcement.Chris Jackson/Getty

Prince William and Kate Middleton pose for photographs in the State Apartments of St James Palace on November 16, 2010 in London, England. After much speculation, Clarence House today announced the engagement of Prince William to Kate Middleton. The couple will get married in either the Spring or Summer of next year and continue to live in North Wales while Prince William works as an air sea rescue pilot for the RAF. The couple became engaged during a recent holiday in Kenya having been together for eight years.

They’re engaged!Prince William and Kate announced their engagementwith a smiley photo call at St. James Palace, where they posed with their arms linked.

03of 20April 2011John Stillwell - WPA/GettyThe newly-dubbed Duke and Duchess of Cambridge sealed their marriage with a kiss on the Buckingham Palace balcony, a highlight of their royal wedding day. In fact, they even went in for a second smooch!

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April 2011

John Stillwell - WPA/Getty

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge kiss on the balcony of Buckingham Palace after getting married on April 29, 2011 in London, England.

The newly-dubbed Duke and Duchess of Cambridge sealed their marriage with a kiss on the Buckingham Palace balcony, a highlight of their royal wedding day. In fact, they even went in for a second smooch!

04of 20April 2011Kate Middleton and Prince William.John Stillwell - WPA Pool/GettyOne day after their nuptials, the happy couple were spotted holding hands as they made their way to a helicopter to embark on their honeymoon.

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Kate Middleton and Prince William.John Stillwell - WPA Pool/Getty

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge walk hand in hand from Buckingham Palace the day after their wedding to a waiting helicopter as they leave for a secret honeymoon location, on April 30, 2011 in London, England. The marriage of Prince William and Catherine Middleton was led by the Archbishop of Canterbury and was attended by 1900 guests, including foreign Royal family members and heads of state. Thousands of well-wishers from around the world have also flocked to London to witness the spectacle and pageantry of the Royal Wedding.

One day after their nuptials, the happy couple were spotted holding hands as they made their way to a helicopter to embark on their honeymoon.

05of 20July 2011Prince William and Kate Middleton.Samir Hussein/WireImageThe newlyweds went on a tour of North America that summer, where they packed in some public displays of affection following a boat race.

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July 2011

Prince William and Kate Middleton.Samir Hussein/WireImage

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge hug after taking part in a dragon boat race at Dalvay-by-the-sea on day 5 of the Royal Couple’s North American Tour, July 4, 2011 in Charlottetown, Prince Edward Island, Canada.

The newlyweds went on a tour of North America that summer, where they packed in some public displays of affection following a boat race.

06of 20July 2011Prince William and Kate Middleton.Chris Jackson/GettyAfterPrince Williamcompeted in a polo match in California, Kate congratulated her husband on the team win with a sweet kiss on the cheek.

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Prince William and Kate Middleton.Chris Jackson/Getty

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge celebrate after Williams' team won the Foundation Polo Challenge at the Santa Barbara Racquet and Polo Club on July 9, 2011 in Santa Barbara, California. The event benefits the American Friends of the Foundation of Prince William and Prince Harry, a charity which supports disadvantaged children, conservation and sustainable development, veterans and military families.

AfterPrince Williamcompeted in a polo match in California, Kate congratulated her husband on the team win with a sweet kiss on the cheek.

07of 20July 2011Kate Middleton and Prince William.DYLAN MARTINEZ/AFP via GettyAt the wedding of Zara and Mike Tindall,Prince Williamgently placed a supportive hand on his wife’s back as they made their way into the ceremony.

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Kate Middleton and Prince William.DYLAN MARTINEZ/AFP via Getty

Prince Harry, Catherine, Duchess of Cambridge, and Prince William arrive for the wedding between England rugby player Mike Tindall and Zara Phillips, the eldest granddaughter of Britain’s Queen Elizabeth II, at Canongate Kirk in Edinburgh, Scotland July 30, 2011. The couple, both world-beating sports stars, tie the knot at Edinburgh’s Canongate Kirk in a private ceremony mid-afternoon that has little in common with that of Phillips' cousin, Prince William, when he married the former Kate Middleton three months ago.

At the wedding of Zara and Mike Tindall,Prince Williamgently placed a supportive hand on his wife’s back as they made their way into the ceremony.

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August 2012

Kate Middleton and Prince William.Pascal Le Segretain/Getty

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge during Day 6 of the London 2012 Olympic Games at Velodrome on August 2, 2012 in London, England.

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September 2016

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge visit The Wave Project on Towan Beach on September 1, 2016 in Newquay, England.

Royal etiquette expertMyka Meier, founder and director ofBeaumont Etiquette, previously told PEOPLE that there areno formal ruleson royal couples being lovey-dovey in public — it’s at their own discretion.

“Senior members of the royal family would likely not be told how to interact or when they can or can not show PDA, and would be trusted to use their better judgment as to when it’s appropriate,” she said. “The royals often adjust PDA to mirror the formality of the event they are attending. At a somber or more formal event, we are less likely to see PDA than at a casual event where it would be deemed more fitting.”

10of 20Kate Middleton and Prince William.Karwai Tang/WireImageKate andPrince Williamcould not help themselves from small displays of affection during their royal tour of Canada.

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Kate Middleton and Prince William.Karwai Tang/WireImage

Catherine, Duchess of Cambridge, Prince William, Duke of Cambridge and Canadian Prime Minister Justin Trudeau attend the Official Welcome Ceremony for the Royal Tour at the British Columbia Legislature on September 24, 2016 in Victoria, Canada.

Kate andPrince Williamcould not help themselves from small displays of affection during their royal tour of Canada.

11of 20September 2016Kate Middleton and Prince William.Pool/Sam Hussein/WireImageKate sweetly put her hand onPrince Williamon several occasions.

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Kate Middleton and Prince William.Pool/Sam Hussein/WireImage

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge sit as stories are read to children at the McBride Museum on September 28, 2016 in Whitehorse, Canada.

Kate sweetly put her hand onPrince Williamon several occasions.

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February 2017

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge join a Team Heads Together London Marathon Training Day at the Queen Elizabeth Olympic Park on February 5, 2017 in London, England.

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June 2017

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge attend day 1 of Royal Ascot at Ascot Racecourse on June 20, 2017 in Ascot, England.

“It is rare to see royal couples holding hands on official outings,” Meier shared. “While we are much less likely to see The Duke and Duchess holding hands in public, we often see Prince Charles and The Duchess of Cornwall holding hands — it’s all simply a matter of preference for each couple and is also likely dependent on the nature of the event they are attending. A more serious engagement would warrant a more serious level of professionalism, which each royal is sure to follow.”

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March 2018

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge attend the annual Irish Guards St Patrick’s Day Parade at Cavalry Barracks on March 17, 2018 in Hounslow, England.

While Kate was pregnant withPrince Louis,Prince Williamplace a protective arm around her during a St. Patrick’s Day outing.

15of 20October 2018Prince William and Kate Middleton.Owen Humphreys - WPA Pool/GettyPrince Williamand Kate were clearly feeling the love in the air atPrincess Eugenie’s wedding. Kate placed her hand in her husband’s lap as they waited for the ceremony to start, and William put his hand over hers.

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October 2018

Prince William and Kate Middleton.Owen Humphreys - WPA Pool/Getty

Prince William, Duke of Cambridge, Catherine, Duchess of Cambridge and Prince Harry, Duke of Sussex attend the wedding of Princess Eugenie of York and Mr. Jack Brooksbank at St. George’s Chapel on October 12, 2018 in Windsor, England.

Prince Williamand Kate were clearly feeling the love in the air atPrincess Eugenie’s wedding. Kate placed her hand in her husband’s lap as they waited for the ceremony to start, and William put his hand over hers.

16of 20March 2020Prince William and Kate Middleton.Tim Rooke/Pool/Samir Hussein/WireImageDuring a visit to Ireland, the pair had some downtime on the cliff walk at Howth. They were spotted posing for a photo with their arms around each other’s backs.

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March 2020

Prince William and Kate Middleton.Tim Rooke/Pool/Samir Hussein/WireImage

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge walk the cliff walk at Howth on March 04, 2020 in Dublin, Ireland.

During a visit to Ireland, the pair had some downtime on the cliff walk at Howth. They were spotted posing for a photo with their arms around each other’s backs.

17of 20August 2020Prince William and Kate Middleton.Ben Birchall - WPA Pool/GettyAsPrince Williamtried his luck at an arcade game, Kate encouraging him with a hand on his side.

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August 2020

Prince William and Kate Middleton.Ben Birchall - WPA Pool/Getty

Prince William, Duke of Cambridge and Catherine, Duchess of Cambridge play a grab a teddy game at Island Leisure Amusement Arcade, where Gavin and Stacey was filmed, during their visit to Barry Island, South Wales, to speak to local business owners about the impact of COVID-19 on the tourism sector on August 5, 2020 in Barry, Wales.

AsPrince Williamtried his luck at an arcade game, Kate encouraging him with a hand on his side.

18of 20March 2022Kate Middleton and Prince William.Samir Hussein - Pool/WireImageKate leaned in close with her hand on her husband’s back during their Caribbean tour.

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March 2022

Kate Middleton and Prince William.Samir Hussein - Pool/WireImage

Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge attend a dinner hosted by the Governor General of Jamaica at King’s House on March 23, 2022 in Kingston, Jamaica.

Kate leaned in close with her hand on her husband’s back during their Caribbean tour.

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July 2022

Catherine, Duchess of Cambridge kisses Prince William, Duke of Cambridge during the prize-giving of the Out-Sourcing Inc. Royal Charity Polo Cup at Guards Polo Club, Flemish Farm on July 6, 2022 in Windsor, England.

A congratulatory kiss! Kate andPrince Williamshared a sweet embrace following a charity polo match.

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Catherine, Duchess of Cambridge and Prince William, Duke of Cambridge attend the Out-Sourcing Inc. Royal Charity Polo Cup at Guards Polo Club, Flemish Farm on July 6, 2022 in Windsor, England.

The royal couple sweetly walked off the field together,Prince Williamholding his arm around Kate.

source: people.com