New movie Superman Henry Cavill never dreamed of becoming the Man Of Steel when he was a schoolboy growing up in England, because he was a chubby kid who landed the nickname 'Fat Cavill'.

The 30 year old will debut as the caped superhero in cinemas this summer (13), and he admits he can't wait for his childhood tormentors to see him toned and athletic on the big screen.

He tells Details magazine, "I was fat... I was Fat Cavill."

The Tudors star reveals he lost 21 pounds (9.5 kilograms) after landing his first big part in a film adaptation of The Count of Monte Cristo at 17, and never looked back: "I lost one and a half stone and I wasn't Fat Cavill anymore."

But he had to bulk up to play Superman and admits he's glad he doesn't have to gobble food like he did as he was preparing to play Clark Kent's alter-ego.

He adds, "I will say I was a lot bigger as Superman... I'm not saying how much. It's modesty about the weight; I've always been worried about my weight. I also don't want to invite that debate: 'Henry weighs this, so he's the perfect Superman.' Or, 'Henry doesn't weigh this, and therefore he's not believable in the role.'

"But I'm not eating 5,000 calories a day anymore."