Actor Josh Hartnett arrives to attend a screening of the film "August" in New York, July 9, 2008.[Agencies]
Josh Hartnett was ordered to give up vegetarianism by his doctor.
The 30-year-old actor had been shooting 'The Black Dahlia' alongside Scarlett Johansson when he fell ill because of his strict diet and workout regime.
He said: "I was shooting a movie in Bulgaria called 'The Black Dahlia' and I was boxing for it. I was kind of anaemic because I wasn't eating very much and I was working out all the time. So I went to the doctors to see what he could do. "
He said to me, 'Do you eat meat?' When I said no, he told me, 'You need to eat meat.' So that was kind of it!" When asked how he coped with eating meat for the first time, the star said: "It wasn't hard at all - it's actually pretty good stuff."
Josh also revealed he is finding it difficult starring in West End play 'Rain Man' in London because of the added pressure of performing in front of a live audience.
He added to BBC Radio 1: "It's just a completely different experience to film because with film you do your take and then you don't get to do it ever again. But with theatre you do it over and over again.
When you watch a film, it doesn't change each time you watch it but with theatre it changes every night."