Former Busted star MATT WILLIS is working with a personal trainer in a bid to lose weight after record bosses expressed dissatisfaction with his appearance. And the British singer has bet his girlfriend, MTV presenter EMMA GRIFFITHS, that he can turn vegetarian for a month. However, Willis is finding it difficult to keep away from the lure of fast food restaurant MCDonald's. He says, "I've just got back from the gym. I've got a personal trainer who kicks my a**. But I'm dreaming of a Big MAC. "And I bet my girlfriend that I could go vegetarian for a month but, standing outside the golden arches, it's so tempting."