E! News caught up with the 47-year-old actor at the SXSW premiere of his forthcoming flick Get Hard, where the funnyman opened up about getting naked for the Etan Cohen-directed movie and revealed his choice fitness regime.
"Now I'm trying to follow in the footsteps of Fifty Shades of Grey," he told E! News. "That's all I'm trying to keep up with. I use the Fifty Shades of Grey diet."
(Not a bad formula, considering Dornan worked out extensively to prepare for the role of Christian Grey.)
In typical Ferrell fashion, the comedian continued to crack jokes, acting as if he was dead serious.
"I don't think it's scandalous at all," he said of the film's telling title. "It promotes men's fitness and awareness of how to keep your body and mind in shape."
Co-starring Kevin Hart, the film centers on James King (Ferrell), who is sentenced to 10 years in prison for fraud and then teams up with Darnell Lewis (Hart)—who has never been to the big house—to teach him how to survive.
As for which celeb Ferrell would pick as his prison protector?
"Probably Martha Stewart because she's already been there," he quipped. "She knows what's going on, you know the ins and outs, who to talk to, who to get cigarettes from."
Get Hard hits theaters March 27.