A new book claims that Freddie Mercury snuck Princess Diana into a gay bar. Credit: Peter Still/Redferns; Tim Graham/Getty Images

Princess Diana . . . as a Drag King! The late, beloved British royal reportedly had a wild night out in the late 80s in which famous friend Freddie Mercury helped her go incognito at a London gay bar -- by disguising William and Harry's mum as a man. In her new memoir The Power of Positive Drinking, British TV actress Cleo Rocos writes that she, the late Queen frontman and comedian Kenny Everett prepped Diana's disguise, dressing her in an army jacket, cap and sunglasses.

Arriving at gay bar Royal Vauxhall Tavern, "we felt she was obviously Princess Diana and would be discovered at any minute," Rocos says (via The Sunday Times). "But people just seemed to blank her. She sort of disappeared. But she loved it."

Diana managed to remain undetected with her three pals, Rocos says, even ordering her own drinks at the bar. The foursome began their adventures earlier that day, drinking champagne and watching reruns of The Golden Girls.

"Diana was in full mischief mode," Rocos wrote of the evening, which is said to have taken place as Diana struggled in her marriage to Prince Charles. "Freddie said, 'Go on, let the girl have some fun.'"