“There are a lot of laughs in this movie, but it’s not just about the laughs,” explains Peter. “It’s really about the story, about a guy who finds his soul and realises what’s truly important.

“For our movies to succeed, audiences must care about the characters,” he insists. “You want Ben Stiller to get together with Cameron Diaz in There’s Something About Mary, and for the schizophrenic cop played by Jim Carrey to figure out the way to Renée Zellweger’s heart in Me, Myself and Irene.”

Shallow Hal is not an idea the Farrellys came up with all on their own. Indeed, the way it reached them sounds a bit like the writing equivalent of Lana Turner being spotted at the soda counter in Schwab’s. For a while, the brothers had been getting letters from a guy called Sean Moynihan, who turned out to be a retired software marketing executive. The letters were very funny, and the Farrellys eventually suggested to Moynihan that he might like to think about screenwriting.

Jack with best friend Mauricio (Jason Alexander)

Moynihan came up with a screenplay called Eye of the Beholder, about a man who could see inner beauty. The brothers liked it and started developing it with him. It took a few years and, at the end of it, out came Shallow Hal.

By then, the Farrellys already had Paltrow in mind for Rosemary: in fact, they had written the part for her, thinking of what Bobby calls the actress’ “ethereal beauty and luminosity that you can’t teach”.

Paltrow, for her part, was intrigued with the idea. “I thought it would be so much fun to work with Peter and Bobby and do something that was different, outside myself and a departure from what people expect of me,” she says. “It was a wonderful break from the corsets, crying and accents that have been such a big part of my career.”

Jack with self-help guru Tony Robbins (played by himself).