Judi Dench once made Lesley Manville wet herself during a production of The Cherry Orchard

Judi Dench is "so naughty," says her friend and former costar Lesley Manville.

"That woman should be locked up!" she declared on Friday's edition of The Graham Norton Show.

After Norton resurfaced an old photo of Dench and Manville in a London production of Anton Chekhov's The Cherry Orchard circa 1989, Manville launched into a spirited (and NSFW) tale that just might make you see the regal Dench in an entirely new light.

"There's a moment in The Cherry Orchard where my character was on their own onstage for a short time," she recounts. "Judi Dench is in the wings trying to make me laugh and she's... how can I put this? She's pretending that she's being pleasured by somebody from behind."

Manville recalls how she was "desperately trying not to laugh," but her efforts were futile. Not only did she laugh, but she laughed so hard that she wet herself onstage. (She blames her pelvic floor; since she'd just given birth, it "wasn't quite what it should've been.")

"It gets worse," she continues. "The stage was raked so I watched my piss trickle down... If you were in the front row you'd have seen it go over the edge."

Tristan Fewings/Getty Images; Andreas Rentz/Getty Images

Thankfully, the long dress she wore onstage was layered enough to spare the majority of the audience from witnessing the soggy results of Dench's prank. Still, very, very naughty.

Manville is set to appear as Princess Margaret during the final two seasons of The Crown, taking over for Helena Bohama Carter.

Season 5 of the royal drama is set to debut on November 9. Watch Manville tell her embarrassing tale on The Graham Norton Show above.

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