Hugh Jackman is scared he's going to suffer a ''heart attack''.

The actor - who stars as the titular character in superhero spin-off 'The Wolverine' - admitted the diet he has to stick to when he gets in shape for the role worries him because he knows it's ''not good''.

Speaking to the Mail on Sunday newspaper's Event Magazine, he said: ''It's not good for me to eat 6,000 calories a day. I have to eat a dozen eggs every day. The only way [varying the diet] works is eating chicken.

''I know there are vegan body builders but chicken is what works for me. Lots and lots of chicken ... I worry I'll have a heart attack.''

The 44-year-old star has to undertake a huge workout regime - which he hates - every time he plays the mutant and he admitted he thought people pushing themselves so hard for a similar goal were ''idiots''.

He added: ''I used to go to the gym and see these guys pumping iron and I thought they were idiots. In what situation could you need to bench 350 pounds? I never understood the addiction, it's just painful. But that's what I do to become Wolverine.''