Kristin Cavallari loves wearing string bikinis to give her "a bit of a butt".

The former 'Hills' star is not happy with her figure despite working out with her trainer three times a week and on the rare occasions when she does don a swimsuit, she will always choose a string bikini to give her some shape.

She told People magazine: "I remember filming 'The Hills' and I saw a photo of myself in a bikini and thought I looked really fat, and I went on a crazy diet. It's hard when people judge you.

"I automatically go to string bikinis now. I really have no shape, and it gives me a bit of a butt."

Kristin blames alcohol for putting on weight because she eats whatever she wants when she is hungover.

She said: "I worked out with my trainer three times a week then did cardio on the treadmill for 40 minutes. But the biggest thing for me was cutting out alcohol; when I'm hungover, I eat whatever I want.

"When I first started dating Jay I gained about 8lbs. And it was like 'I've got to get back to the gym. I can't eat like a 6'4" guy!"