Emma Thompson is one of the UK's most successful actresses, commanding the screen with her enigmatic roles over three decades in showbusiness.
While receiving a damehood at Buckingham Palace on November 7, the 59-year-old actress made Prince William blush with her cheeky comment.
She said, "I love Prince William, I’ve known him since he was little, and we just sniggered at each other.
"I said, "I can’t kiss you, can I?" And he said, "No don’t"!
"If you’re first up you have to be more formal on such an occasion, but he’s looking wonderful and doing so well. He said, 'This day isn’t about me, it’s about you'."
"It’s really lovely because I’ve always loved the boys and I’ve always been a long-term correspondent with their dad, it’s a very lovely feeling."
Thompson, now Dame Emma, was being recognised in the Queen's Birthday Honours for her services to drama.
She wore white trainers and a navy Stella McCartney suit to the ceremony, with the choice of designer a representation of British fashion, she said.
Sporting a Fawcett Society Equal Pay badge, Dame Emma said she hopes to use her damehood to bring attention to children going hungry in the school holidays, known as holiday hunger.
She said: "This is a very rich country with hundreds of thousands of children who don’t get enough to eat.
"I’m sorry, but that’s just rubbish. I’m going, why isn’t this top of the list? We have kids begging in schools for leftover food, that’s just awful."
The actress was joined by her long-time husband Greg Wise and their two children - Gaia, 18, and son, Tindyebwa Agaba Wise, a Rwandan orphan they informally adopted in 2003 when he was 14 - for the momentous occasion.
Watch Emma and William's hilarious interaction below.