Perpetual menace George Clooney claims he is working on the prank to end all pranks – and Brad Pitt’s career.

Since pairing up in Ocean’s Eleven 15 years ago, the actors have been as thick as thieves, and dedicated to making each other’s lives hell.

Famous instances include Clooney slapping a bumper sticker on Pitt’s new Toyota Prius depicting a marijuana plant with the message “F*** cops”.

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During filming for Ocean’s Twelve, Clooney assembled a crowd outside Pitt’s window and got them to chant “George! George!” all night.

Brad Pitt has tried to keep up over the years, once telling Italian locals while shooting on location that Clooney would only answer to the name ‘Danny Ocean’ (his character in the Ocean’s series) and did not like to be looked directly in the eyes.

But Clooney now claims to have the ultimate prank up his sleeve.

“I am working on a prank that will end his career,” Clooney told Vanity Fair recently.

“If you take the time, if you’re willing to sit on one for a couple of years, and just plant the seed … there’s no rush.”

The actor, who most recently starred in the Coen Brothers’ latest Hail Caesar, didn’t let on anymore about the prank, but his history suggests he’s willing to do anything.

While working on Ocean’s Twelve with Julia Roberts, Clooney positioned a bucket of water above Roberts’ door so it would tip on her when she opened it, but a bell boy unfortunately copped the spray himself.

He also sent Oscar-winning industry legend Meryl Streep a dialect instruction DVD and signed it from Brad Pitt, as well as a fake letter of complaint to Tina Fey and Amy Poehler after their monologue at the Golden Globes and signed it from Matt Damon.

Despite turning 55 this year, Clooney is showing no signs of scaling back the hijinks.