Hugh Jackman lives in fear that his extreme movie diets will lead to a heart attack.

The Australian actor bulks up every time he has to play superhero Wolverine, both in the X-Men franchise and in the character's own spin-off film series, and he binges on chicken and eggs to reach a target of 6,000 calories a day.

Jackman also famously lost weight to play Jean Valjean in 2012's Les Miserables, consuming nothing but liquids to shed the pounds, and the actor admits his extreme dieting may end up having a serious effect on his health.

He tells Britain's Notebook magazine, "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 that seems to work is eating chicken... Lots and lots of chicken... I worry I'll have a heart attack."