"He went behind the scenes and had incredible access to talent and crew and has made a documentary that is not yet complete, which shows the challenges of making the film — the tolls it takes on actors and crew," Barron said. "It's not just pure gloss and everybody's happy. It's real. ... At the same time, it's really, really funny."

"Morgan comes in to interview Dan in his dressing room, and Dan says, 'Will you wait one second? I want to watch the 2:50 at Doncaster,' which is a horse race. He says, 'Yeah, I bet on it.' 'How much?' 'Ten quid.' And the horse, of course, comes in way behind the pack."

"It was a very well-documented production. We had a crew filming behind the scenes for the entire production, which is unheard of — and that's been for all the films," Barron explained. "There is material, and we'll see how it's used. I'm sure Warner Bros. will package it in some form or another."