Josh Brolin called in experts to help him gain weight for new film

Josh Brolin called on top doctors to advise him how to safely pile on the pounds as he prepared to make Oldboy with moviemaker Spike Lee.

He told the director he wanted his tough guy character to be a bigger man and set about putting on weight for the role, but Lee insisted he did it safely.

The filmmaker says, "He gained 50 pounds for the role. He met with a bunch of doctors and dietitians that came with a safe program for him to gain weight and to lose weight over a relatively short amount of time.

"The way it was explained to me was most of the weight he gained was water. When he had to lose it he had to lose 20 or 30 pounds over a weekend."

Lee reveals the weight gain and loss really took its toll on his leading man's moods.

He adds, "It affected his personality. (Robert) De Niro talked about the month of depression after doing Raging Bull and the weight he had to gain for that. Right now, it's much more advanced and doesn't take months to lose the weight, but it does affect your psychology. You can't be happy about it. You become another person with that weight gain."