Paris Hilton is hitting the gym five times a week.

The 30-year-old heiress has started working out almost every day with her boyfriend, Las Vegas nightclub manager Cy Waits, and is getting addicted to hitting the gym.

A friend of the star explained: "She has given up her lazy girl ways and is finally in a routine that has her hitting the gym five days a week.

"It's all down to Cy. He spends two hours in the gym every day. He loves lifting weights, and it's really rubbed off on Paris. Now they work out together."

The blonde beauty has also drastically altered her diet, but has actually upped her daily calorie intake to account for her gym sessions.

The source added: "She's never been a big eater. But now, she finishes a hard workout and she's starving. So, she's burning more calories, but she's eating more, too! Cy does all the cooking and he's super-healthy."