Hugh Jackman struggled with filming the musical numbers in 'Les Miserables'.
The actor - who has won a host of awards for his stage performance work - says his melodramatic turn as the film's hero Valjean was taxing as lip-synching to a live pianist made him "struggle" but he still enjoyed the experience.
He said: "I think trying to mime something is really odd. So much of your brain is on miming whereas here we have live piano, so if you're crying and you want to take a second, the pianist just pauses.
"By take 23, you want to go, 'Hello? Human being here! I'm struggling.' But generally it's actually really freeing.
"I'm a bit of an ignoramus when it comes to musical theatre. I always feel like an actor who stumbled into it. Valjean is a difficult sing with a huge range. I wanted to get in shape."
Despite tabloid tales of bitter rivalry between Jackman and his co-star Russell Crowe, the actor says he and 'The Gladiator' star have a brotherly relationship and strengthened their bond while shooting the drama.
Hugh said: "Valjean battles with feelings about himself - who he is, the feeling that he is falling short - and Javert plays on that. Russell and I have known each other for ages, he is like an older brother to me.
"My publicist sent me something in the press about how I enjoy beating him up. I sent it to him and we both had a laugh about it. We actually bond together over this in every way."