Bradley Cooper has swapped the film set for flipping burgers, working at a fast food restaurant in London.
The Oscar-nominated heartthrob, who next voices Rocket Raccoon in Guardians Of The Galaxy, surprised customers at a branch of Burger King in London's Leicester Square as he served them at the counter and rustled up Whoppers, reported The Sun.
The American Hustle star spent the evening of Sunday July 27 at the restaurant learning how to flip burgers, cook fries and other tricks of the trade in preparation for his new comedy, in which he plays a chef. He later shot some scenes at the same venue.
A source told the newspaper: "Bradley was training alongside genuine Burger King staff. The aim was to learn the 'art of the flip' which he nailed fairly quickly.
"There was no real fanfare from him. You'd never know he was a big star by the way he spoke to people," the insider added.
The film, formerly known as Chef, tells the story of Bradley's character creating a 'dream team' to launch the best restaurant around.
Directed by August: Osage County filmmaker John Wells, the comedy also stars Emma Thompson and Jamie Dornan.
It is now referred to as 'Adam Jones' until the final title is decided, due to the recent release of Jon Favreau's film, Chef.
"Even though our writer Steven Knight claims we had the rights first, Jon Favreau killed us and made a great movie that we all love," producer Harvey Weinstein told Deadline.
"And while our film deals with cooking, it's about different things..."
Referring to The Weinstein Company's title dispute with Warner Bros last year over Lee Daniel's The Butler, he joked: "We tried to get Lee Daniels' Chef Movie but Warner Brothers got there first and didn't give it to us, so now we're calling it the Untitled John Wells project."