Kate Middleton dressed up as Cheryl Cole on her hen night
The Duchess donned Chezza's military-style outfit for her last night out as a single woman and even performed one of the singer's hit singles.
Cheryl, 29, explains in her new autobiography Cheryl: My Story: "Kate confessed that she dressed up as me on her hen night, in a body suit and split trousers and sang Fight For This Love.
"She even learned the dance routine and was step perfect by all accounts, as her sister Pippa and brother James also came over and told me all about it.
"I could just imagine her and it was so surreal."
Kate and Prince William - who married in April 2011 - told Cheryl all about the hen night after the Queen's jubilee concert in June.
Cheryl goes on to reveal that Wills, 30, even asked her: “Did you know you’ve got a bit of competition?!”
Kate invited just a few girls to her low-key hen do, which was held at the home of a close friend.
Guests included businessman Richard Branson's daughter Holly and Kate's former university flatmate, Olivia Bleasdale.
Cheryl has a rather good relationship with the Royal Family.
She gushed earlier this year that Kate, 30, had told her she's a big fan of her music.
Cheryl said: "Kate is really down to earth. We talked about fashion and she said she loved my music.
"She was incredibly girly and sweet."
But Cheryl has an even bigger admirer in Kate's brother-in-law, Prince Harry.
The Prince confessed to Cheryl's X Factor pal Joe McElderry in 2009 that he was "so jealous" he "got to spend weeks with Cheryl".
And - before Cheryl hooked up with her now boyfriend Tre Holloway - the feeling was most definitely mutual.
She said earlier this year: "Everybody knows I have a soft spot for Harry. He's cute.
"I've met him several times and we laugh about it. It's a bit of banter between us.
"He's so ordinary and a normal 27-year-old who is living in a crazy world and we can bond over that."