Colin Farrell channeled 'The Biggest Loser' to get his body buff for 'Total Recall'

"Total Recall" star Colin Farrell took a decidedly low-rent approach to getting in Arnold Schwarzenegger-style shape for the action classic reboot.

He watched “The Biggest Loser.”

“One of my favorite shows on television is ‘The Biggest Loser.’ When people that size can lose weight and get healthy again, it is possible for anyone," he told FOX411's Pop Tarts column. “I ate lots of greens and chicken, I didn’t order dessert for four months. I stayed off the sugar and got myself on the treadmill. It’s just discipline and not that hard when you apply the science to it."

Co-star Jessica Biel, who's one of the fittest actresses in Hollywood, and who previously starred in action flicks like “Blade: Trinity” and “The A-Team,” didn't have to do much of in the way of body transformation. She did however have to remind herself all of the movie fighting is make believe.

“The best thing about being an action star is getting to learn really cool martial arts and you feel like you can kick ass in life, but you cannot. You have to remember that,” she told FOX411’s Pop Tarts column. “I think I have an unhealthy view of myself, it I were to get into trouble I would do a routine I learned a year ago, so you have to be careful with that.”

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Directed by Len Wiseman, “Total Recall” is based on the 1990 Arnold Schwarzenegger/Sharon Stone hit, yet the mood on this set was altered somewhat by the fact that Wiseman’s wife Kate Beckinsale was also playing a hard-core action superstar.

“I freaked out that I was going to hit [Kate] and make a mistake and clock her in the jaw. Thankfully, it didn’t happen and we were just apologizing to each other,” Biel said. “But I was fighting the director’s wife here, so that was a little nerve-wracking.”

Biel wasn’t the only one slightly put out by the husband/wife director/star dynamic. Farrell, who plays factory worker Douglas Quaid, was also on pins and needles in some scenes with Beckinsale.

“I remember hitting Kate, directors are always concerned when actors get hurt, but this was a little more – I slapped his wife,” Farrell said. “First I kissed her, then I slapped her.”

Beckinsale said all of the onscreen butt-kicking was “cool,” but the scenes where she and Biel go at it are the best.

“It is very exciting for both men and women to see women kicking ass like that,” she added. “It’s empowering.”