Ryan Reynolds worries he's too old to play a superhero.
The 38-year-old actor plays Deadpool in the upcoming comic book adaptation but admitted working out for the role was physically gruelling, as he put his back out on the first day of training.
He said: "On the first day I put my back out. I was lying on the floor at 6am, the gym was empty, I didn't even have my phone.
"I crawled, I couldn't move so I literally crawled on all fours, two blocks home."
Ryan previously played the character of Deadpool in 'X-Men Origins: Wolverine' and played the titular superhero in 2011 movie 'Green Lantern' but revealed that getting in to shape for 'Deadpool' was tough.
He told the Observer magazine: "The last time I trained for a film like this was five years ago. It's a big difference. Now I mean... you start to wonder if you even still have abs under there."
Meanwhile, director Tim Miller recently said he can't imagine anyone else taking on the role other than Ryan.
He said: "I just never saw anyone else apart from Ryan. In real life, he pretty much is Deadpool. I couldn't think of anyone else who had the combination of good looks, athleticism, dramatic chops - because he's a great dramatic actor - and, more importantly, comedy on top. He's got that same smart, offbeat sense of humour. He's f**king raunchy."