Prince William and Duchess Kate are still gold on their 10th wedding anniversary

Prince William and Duchess Kate celebrate their 10th wedding anniversary on Thursday, making the couple the most successful royal marriage so far of Queen Elizabeth II's six adult grandchildren.

It's probably safe to expect the two will not be exchanging presents made of tin, even though it's traditional for 10th anniversaries: It symbolizes a successful marriage that's flexible and durable, one that can bend without breaking.

That certainly sums up the union of the Duke and Duchess of Cambridge, but maybe diamonds and gold might be a better choice for a future king and his queen consort.

On Wednesday, the Cambridges released two new photo portraits for the occasion, both taken this week at Kensington Palace by photographer Chris Floyd. The pictures show the couple in cuddly poses, holding hands or arms wrapped around each other.

They're dressed casually and smiling broadly. He's wearing a blue sweater, shirt and pants; she's wearing a blue patterned wrap dress of a sheer material. In one photo, they appear to be standing in a palace courtyard, in the other they're sitting in the grass.

On Thursday, they released a video of the entire family playing outdoors in Norfolk in the fall of last year, standing on a beach, running through woods and roasting marshmallows on a fire.

The video, filmed by Will Warr and posted on Twitter and Instagram, was accompanied by a message:

“Thank you to everyone for the kind messages on our wedding anniversary. We are enormously grateful for the 10 years of support we have received in our lives as a family. W & C”

But it is unlikely the couple will publicly disclose their private plans to mark the anniversary of their spectacular wedding on April 29, 2011, at Westminster Abbey in London.

With the U.K. still in lockdown for indoor entertaining, it's likely to be a low-key celebration, advises filmmaker Nick Bullen, who's been making documentaries about the royals for decades and is editor in chief and co-founder of True Royalty TV, the subscription TV channel for royal superfans worldwide.

There will be Zooming, predicts royal commentator Richard Fitzwilliams. "Perhaps they will be sharing a new photograph from their big day," Fitzwilliams says.

Happy anniversary! Prince William, Duchess Kate share new romantic photos

In fact, their fans would love to see a few behind-the-scenes pictures of their memorable wedding, viewed by millions worldwide (50 million people in the U.K. and America alone). The nuptials were moving, music-filled and joyful, and later the couple kissed – twice! – on the balcony of Buckingham Palace.

Once was not enough for the half-million cheering, screaming, flag-waving admirers amassed outside the palace gates. "More, more, more!" the crowd shouted. So they pecked each other again.

The Duke and Duchess of Cambridge are stepping up their royal duties

As scandal and recriminations batter the British royal family, pro-monarchists – which is to say, most Brits – increasingly look to the Cambridges to step up to support his father, Prince Charles, as he takes over more duties from the 95-year-old queen.

When the queen's husband, Prince Philip, died on April 9 just short of his 100th birthday, William eulogized his grandfather as a man defined by service to country, Commonwealth, queen and family. He pledged to emulate him, saying in a statement, "I will miss my Grandpa, but I know he would want us to get on with the job."

It's a vow that shows the Duke of Cambridge's dedication to his role and his preparation for the future. "Every sentence in that statement told a story, that the future of the monarchy is in safe hands with the Cambridges," Fitzwilliams says.

William and Kate seem fully ready for the responsibility: They appear to be happy and healthy (despite Will's bout with COVID-19), attentive parents, and graceful, hard-working representatives of the queen.

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"It is abundantly clear that Prince William, with Catherine by his side, has really stepped up to the plate," Bullen says. "They have both been a key face of the monarchy throughout the pandemic and he will be taking on even more of a role as the Prince of Wales steps closer to the throne.

"There is absolutely no doubt that the William and Kate partnership is a winning one for the royal family."

Kate has grown in confidence in the 10 years since the wedding, Fitzwilliams says, and has helped humanize the royal family, making them seem less remote.

When a young London woman disappeared on a walk home at night in March and was later found dead, Kate turned up to lay flowers at her ad hoc memorial at Clapham Common in South London.

Will and Kate have been especially prominent leaders in the royal family's efforts to highlight the work of the National Health Service during the pandemic and the need to follow lockdown restrictions and get vaccinated.

The two were on the job this week, carrying out their first in-person away engagement this year, in County Durham, where they visited a fifth-generation family farm and a local youth charity that received donations from the couple's Royal Wedding Charitable Gift Fund.

They looked like they were having a blast perched on hay bales, petting lambs and taking a few golf swings at the Cheesy Waffles Project charity.

Prince William and Duchess Kate rival the Queen in popularity

For their efforts, the Cambridges have earned high marks in a recent YouGov popularity poll, which found that William is the most popular royal, with a 74% approval rating, followed closely by the queen at 72% and Kate at 67%.

If at one time, William, who will be 39 in June, felt a little leery of his fate as a future Prince of Wales and eventually as king, he seems to have embraced his destiny with support from the former Kate Middleton, 39, who has proved to be a true partner in the tricky business of being "real" and royal in a 21st-century constitutional monarchy.

"Catherine has gone from blushing bride to a queen-in-the-making over the last 10 years," Bullen says. "She is the royal family's 'not-so-secret' weapon."

They don't need to be lovey-dovey in public for people to recognize their devotion to each other and to duty.

Bullen says Brits can see the Cambridge children – Prince George 7, Princess Charlotte, soon-to-be 6, and Prince Louis, 3 – are happy and secure beneficiaries of hands-on parenting.

Will and Kate will need each other going forward, as their duties are increasingly more demanding as other senior royals – such as scandal-plagued Prince Andrew (owing to his relationship with convicted American sex offender Jeffrey Epstein) – have stepped back from public duties.

"William and Kate are all too conscious that the future of the monarchy rests on their shoulders and that of their family," says Fitzwilliams.

Prince Louis turns 3! Duchess Kate shares new birthday photo of the youngest Cambridge

Meanwhile, William's rift with his beloved brother Prince Harry, 36, and his wife, former American actress Meghan Markle, 39, has widened in the wake of the Duke and Duchess of Sussex's shattering interview with Oprah Winfrey in March.

The Sussexes told Winfrey they fled to California to escape racism in the British media and in his family, and because Meghan received no support from the palace when she became suicidal over the pressures of being in the royal family.

William, who almost never talks to reporters about his family, felt strongly enough to respond to a question a few days later when he and Kate visited a London school.

"We're very much not a racist family," he declared.

"It has been both sad and shocking to watch," Fitzwilliams says. "William sees Harry and Meghan’s interview as a betrayal of his family. Harry sees William as trapped within a sclerotic institution."

No matter how wounded the feelings on both sides, William and Kate are carrying on, mixing earnest advocacy for their causes with increasingly relaxed social media posts.

Last month, the Cambridges visited Westminster Abbey, striding down the aisle where they glided 10 years ago, to visit a pop-up vaccination site set up in the 1,000-year-old abbey.

They offered encouragement to people getting their jabs, and later had a private moment of reflection in remembrance of those who have died from COVID-19.

Earlier, on March 17, they posted a surprise video in honor of St. Patrick's Day, which featured the couple in a flirty exchange: Kate was seen smiling at her husband as he joked about her having the "easy bit" to say. He, on the other hand, had to say "Happy St. Patrick's Day" in exceptionally difficult Irish Gaelic.

A decade later, Will and Kate's royal wedding is fondly remembered

Even if the Cambridges are mum about their anniversary plans, others are not.

The BBC will replay the spectacle and pageantry in "Royal Wedding: A Day to Remember." The special will look at the wedding through the eyes of those who were there, from the then-Archbishop of Canterbury to the scores of ordinary citizens who slept on the street the night before.

The queen's marriage to Prince Philip lasted 73 years, but multiple royal marriages have failed since they wed in 1947: Her sister, the late Princess Margaret; three of the queen's four children (all but the youngest, Prince Edward, and his wife, Countess Sophie); her nephew, Margaret's son David Armstrong-Jones, Earl of Snowdon, who announced last year he and his wife, Countess Serena, were divorcing, and her eldest grandson, Peter Phillips, son of Princess Anne, who announced a split from his wife, Autumn, last year.

You can never be too sure of these things – after all, look what happened to the so-called fairy tale-marriage of William's parents – but the union of the Duke and Duchess of Cambridge seems solid.

This article originally appeared on USA TODAY: Prince William, Kate Middleton's anniversary photos melt our hearts