Russell Crowe has piled on four and a half stone for his latest movie role thanks to a cheeseburger-based diet.

The former hearthrob looked almost unrecognisable as he stepped out in L.A. yesterday sporting an impressive belly and long locks.

His newly-expanded frame is apparently down to the actor dining on cheeseburgers three times a day.

Russ with his new bulky frame (left) and a slimline Russ in 2005 (right)

'I'll have the cheeseburger for breakfast, thank you,'  he joked of his approach to weight gain.

He also admitted that he is snacking on sweet treats including cupcakes to bulk up.

The chunky star will be playing a bloated and manipulative CIA boss in new flick Body of Lies alongside Leonardo DiCaprio.

See other stars who have piled on the pounds here