Billy Crystal reveals Princess Diana's reaction to When Harry Met ...

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Billy Crystal has revealed Princess Diana's reaction to the infamous restaurant scene in When Harry Met Sallyat the film's London premiere in 1989.

The actor, 76, featured in the hit romantic comedy opposite Meg Ryan, and in one legendary scene, Crystal and Ryan’s characters, Harry and Sally, are dining in New York City’s Katz’s Delicatessen.

As the two debate whether Harry can decipher the difference between a woman’s real or faked orgasm, Sally unexpectedly begins to loudly pretend to climax, to prove a point.

"Everybody knew about it, but I don't think she did," Crystal said of the royal.

"She starts laughing this incredibly guttural sound... If it was a date, I don't think I'd see her again," he joked.