Prince Louis and Princess Charlotte's adorable encounter with Joan Collins shows just how polite the young royals are

Prince Louis is well-loved for his cheeky nature, often stealing the show at royal events. But when he and older sister Princess Charlotte met showbiz royalty Joan Collins, the young royals were super polite.

In her book, Behind The Shoulder Pads, Dynasty star Joan Collins recalls how she was so nervous when she met Kate Middleton along with Louis and Charlotte during the late Queen's Platinum Jubilee celebrations, she forgot to curtsey.

The actress took part in a motorcade down The Mall during the celebrations and was joined in the procession by fashion model Twiggy and GBBO judge Prue Leith for the 'Dames in their Jags' section of the pageant, which took place on the last day of the festivities.

Joan wrote, "Finally, we arrived outside the Royal Box, which was packed with royals and relatives of the Queen. 

"As we descended from the Jaguar, trying to look presentable after two hours in the freezing wind, Princess Beatrice and her husband Edoardo waved at us excitedly. Then he nudged Princess Anne, who nudged Prince Charles and Camilla, and they all waved, smiled at us, and mouthed, 'Well done!' Very gratifying indeed." 

She added, "Shown to the green retiring room behind the box, I collapsed onto a sofa and was offered a cup of tea. Suddenly, a vision appeared in a red dress. Catherine, the [then] Duchess of Cambridge, with her two young children in tow."

But while it's protocol to curtsey to senior members of the Royal Family, Joan was so star-struck she forgot. Joan continued, "'Hello, Joan,' she said sweetly, holding out her hand. 'Hello, ma'am,' I gulped, forgetting to curtsy."

And recalling how Princess Catherine introduced her two youngest children, Joan added, "'This is Charlotte, and this is Louis,' she said, and both little people held out their tiny hands politely for a handshake."

Prince William, Kate and their three children, Prince George, Princess Charlotte and Prince Louis watched the pageant from the royal box with extended members of the late Queen's family.

And it was here that Prince Louis famously stole the show with his cheeky antics, including sticking out his tongue and and clamping his hands over his ears on the Buckingham Palace balcony as the royals awaited the Red Arrows. He was even warned by Mike Tindall, who is married to Princess Anne's daughter Zara, to behave as he appeared to say "I'm watching you!" while he signalled to his eyes with his two fingers.

Speaking about the incident, Mike later said, "Louis, he was just wanting to have fun. And my two are always mischievous so it's trying to keep a lid on. There were a lot of sweets out back though, so there was a real sugar high. It's tough for them. They're all young… it's a long time. But as any parent knows you just do whatever needs to be done."