Bale, 37, said he wanted to "piss on that guy's shoes" for inferring that the physical transformations he underwent for roles in The Fighter, The Machinist and Rescue Dawn were easy.

"'To be honest, I find it laughable that it's considered to be some f---ing gimmick - it's so patronising," he said in an interview with the Australian edition of Empire Magazine, the Daily Mail reported.

"For God's sake, do people not understand what a pain it is to do?

"It's as though it's some comment about, 'Oh it's easy for him, because he's done it a bunch of times.'

"It's not easy, it's not fun - it's horrible."

Bale, 37, received critical acclaim for his supporting role as Dicky Ekland, a drug-addicted former boxer, in The Fighter.

He exhibits a remarkable likeness to the real-life Eklund in terms of his physicality and mannerisms.

In 2004, Bale lost a reported 28 kilograms to play an insomniac in The Machinist.

Two years later he shed weight again to film Rescue Dawn, the film adaptation of the story of German-American pilot Dieter Dengler, whose plane was shot down during the Vietnam War.

Speaking about The Fighter, in which he stars with Mark Wahlberg, Amy Adams and Melisa Leo, the actor told Empire Magazine: "I would never pick to do that, but it's a part that I like and he's a welterweight and he's a crackhead.

"I don't know about you, but I've never seen a welterweight with any fat on him - or a crackhead.

"So it's just what you end up having to do. Somebody told me that somebody wrote something about my 'trademark weight loss'.

"I'd just like to piss on that guy's shoes."

It is not the first time Bale has given people a spray. His meltdown on the set of Terminator: Salvation was made public when someone leaked an audio recording.

The film's producer and assistant director later came to the actor's defence, clarifying that it was sparked during the most emotional scene in the movie and "it was just a moment and it passed".

smh.com.au