Joaquin Phoenix wanted to gain weight for 'Joker'.

Joaquin Phoenix as Joker

Joaquin Phoenix as Joker

The 44-year-old actor ended up losing 52lbs to play the title role in the Clown Prince of Crime's highly anticipated standalone blockbuster, but he admitted initially he hoped to get overweight for the role instead.

Speaking on the 'ReelBlend' podcast, he explained: "It just seemed like it would be easier. [laughs]

"The very first bit of research that I did was about medication and the side effects of medication and everybody on these boards was talking about these dramatic changes in their weight.

"Whether it be putting on weight or losing weight. There's something so f***ing tragic about taking a medication because you feel out of step with the world, and then you have these side effects that magnify that feeling."

When Phoenix approached director Todd Phillips with the idea of gaining weight - which was mainly because he hasn't enjoyed shedding it for other roles - he was overruled.

He added: "And so I just to Todd [Phillips] 'I think we need to have something that is drastic to kind of show this, and it's based in reality and I think it's really worth exploring.'

"And I suggested we put on weight because I've done the losing-weight thing before, and it sucks! [laughs] I was like, 'I don't want to do that again!'

"But Todd was really smart, and he said, 'No, I really think it's the other way.' And I knew it was going to be that way, but I just wanted to give it one little [shot]."

Phillips' suggested proved to be the right one, and Phoenix admitted the weight loss helped him connect with the character of Batman's great rival and his comedian alter ego Arthur Fleck.

He said: "Arthur is somebody who is constantly searching for validation and acknowledgement and love. Like he just wants to consume people's adoration. It's what he needs. And I think in some ways, I had that feeling.

"I was constantly dissatisfied, having that kind of level of hunger makes you just think differently. But I think it also made me feel my body in a way that I don't normally kind of feel, you know, and allowed me to find a lot of the movement that ended up becoming such an important part of the character."