Benji Madden has reportedly lost 5lbs after being put on a strict diet by Cameron Diaz.

The 35-year-old Good Charlotte rocker started dating the lithe actress three months ago.

But while the pair are rumoured to be happier than ever, Cameron, 41, is said to have done her best to introduce some changes to her beau’s lifestyle.

“Cameron watches every morsel of food that passes Benji’s lips,” a source told the American edition of OK! Magazine.

“Benji’s whipped, so he’s doing what he can to please Cameron. He’s already lost five pounds.”

After realising that late night snacks during recording sessions had contributed to Benji’s paunchier than usual figure, Cameron supposedly instituted a strict dietary regimen.

In addition, she is believed to have asked Benji to get rid of some of his numerous tattoos once he gets back into shape.

It was recently reported things are going so well between Cameron and Benji she is considering heading up the aisle for the first time.

“Cameron has told close friends that she can really see herself settling down with Benji,” an insider told Life & Style magazine. “She’s been boasting to pals that she’s never had sexual chemistry with anyone like she has with Benji.”

Cameron has previously said that marriage wasn’t something that she had been “drawn to”. But with Benji, she seems to have found her soul mate, and the possibility of marriage isn’t only coming from one side of the relationship.

“Benji is so head over heels for her,” the insider revealed to the publication. “He believes he’d be the luckiest guy in the world to wed Cameron.”