Christian Bale went on 2am runs to prepare for his role in 'The Fighter'.

The actor embarked on a strict diet-and-exercise regime to play drug-addicted former boxer-and-trainer Dicky Eklund in the biographical movie and insists he never felt better than when he was shedding 30lbs off his already trim frame.

He said: "It felt great. I was running all the bloody time. I was like an Energizer bunny - I just kept going.

"I'd wake up at two in the morning and say, 'I think I'll go for a run.' It was stupid but I felt really good."

While preparing for his pugilistic role, Christian spent time with Dicky and toured many of his old dangerous hangouts with the faded sportsman.

He added to Total Film magazine: "I got to go round with Dicky and go to the different crack-houses he used to hang out in.

"The window he jumps out of in the movie was the actual house."

The actor's dedication to the role impressed both his co-stars and director David O. Russell.

David said: "When Christian sees something that turns him on, something in him clicks. He shaved a bald spot in his hair, hung out with Dicky and just inhaled him, he became him."

Christian stars alongside Mark Wahlberg in 'The Fighter'.

Mark plays Irish/American boxer Micky Ward who is trained for his Welterweight World Championship bout by half-brother Dicky and was nominated for the Best Actor Golden Globe earlier this month.