Nicholas Hoult has been "working out" to play Lex Luthor.

The 34-year-old actor has been cast as the villain in James Gunn's upcoming 'Superman' movie and he's opened up about his preparations prior to filming revealing he's been hitting the gym because he wants his portrayal of the man of steel's arch nemesis to have real muscles.

During an appearance on the 'Inside of You' podcast, he explained the idea stems from a Superman comic, saying: "I have been working out. There’s that bit in ‘All-Star Superman’ [comic] where he [Lex] talks about his muscles being real and hard work and all that. I kind of took that as a little bit of a fuel for the fire."

The podcast was hosted by fellow actor Michael Rosenbaum - who previously played Lex in TV show 'Smallville' - and Nicholas admitted the series was the first time he'd seen the bald baddie onscreen.

He told the presenter: "The first ever Lex I saw was you. I grew up and ‘Smallville’ was on ... I was like 11 or 12. So that was the show I would watch, and it was the first iterations I would see of Superman and Lex and all those stories. So it's kind of bizarre to be sitting across from you.

"Since I've seen Richard Donner’s movies and all the other ones and kind of seen some of the other performances but you’re like the one … I love your portrayal. Are you kidding me? It’s the best."

Nicholas went on to reveal he would be shaving his head to play Lex but was still in the "mental preparation zone" as he recorded the episode prior to filming.

'Superman' features David Corenswet in the title role it's due for release in July 2025.