If you need actorly advice about playing an overweight politician and you've got the number of a guy who won an Oscar for playing an overweight politician, you give him a ring. So, naturally, Christian Bale called up Gary Oldman ahead of his remarkable transformation into George W Bush's vice-president and occasional Elmer Fudd-ish hunter Dick Cheney for Adam McKay's Vice. However, Bale didn't heed Oldman's advice.

The strain of putting on all that weight was starting to freak Bale out. Slightly too far along the line to be able to back out of putting on the weight, he thought he'd give Oldman a shout.

"I talked to Gary about all of that," Bale explained to Sam Rockwell for Variety. "We had very different approaches to it. I had said, 'I don’t know how to do this except I’ve got to gain the weight myself.' I was in the middle of doing that. I was a large toddler. I called up Gary and I said, 'How much weight did you gain for the role?' And he said, 'I didn’t gain anything.' I went, 'What?' I was already well down the track. I felt like such an idiot. I didn’t understand that [prosthetics and makeup] had come such a long way."

Bale went on to talk about getting inside the mind of one of the most contentious politicians of post-war American politics, and explained that he wanted to be able to pitch Cheney as exactly the free-thinking political genius Cheney thought he was.

"There’s no interest to me in making a film where my opinions are in there," Bale said. "Adam [McKay] is the storyteller and we agreed early on, let me counter his points of view. Let me advocate for Cheney. Let me try to convince him, because I do believe Cheney is a very strong-minded individual. The nature of 'What does it mean to be a patriot?' That’s a real amorphous word. It’s like 'obsession'. It can be a healthy thing, it can be incredibly unhealthy as well."