Hugh Jackman thought he'd broken his neck while filming 'The Wolverine'.

The 44-year-old star narrowly avoided a bad injury when a stunt on top of a train almost went wrong and while his wife Deborra-lee Furness made him admit he isn't ''invincible'', he revealed he will keep up as much as he can while he's still fit and able.

He said: ''It doesn't get any easier [with action roles], that's for sure. I almost broke my neck doing a stunt.

''Literally, there's one scene [in 'The Wolverine'] on a bullet train where I swing out from inside to outside, and my neck got caught and I actually thought I broke my neck.

''I went home early that day and it was one of those moments where my wife looked at me and was like, 'What are you doing? It's enough playing around in the schoolyard but you are not invincible'. It hits me all the time. But I do whatever I can for an old man.''

Despite the high-risk nature of some of his roles, Hugh admitted it's the fitness regime he undergoes for the parts which hit him hardest.

He added: ''For me, the toughest bit is always the training at 4am and eating chicken breasts seven times a day.

''This is my only vice right now. Coffee. And I can't even have sugar in it ... Deb is an actress so she knows what a crash diet is so she is really understanding.''