Kelly Brook not motivated when she's happy

Kelly Brook finds it hard work keeping fit when she's content with her love life.

The former 'One Big Happy' actress is very happy in her relationship with Jeremy Parisi but admitted feeling so secure makes her lose her motivation to work out.

Asked what her biggest challenges are with her fitness, she told new! magazine: "Being in a comfort zone.

"When I'm happy and everything is going well at work, and everything's going well in my relationships and my home life, I fell it's hard to get motivated.

"I'm so happy in my life at the moment, but I had many years where I wasn't and it was so much easier to go to the gym because it was a way of switching off."

It comes after the 38-year-old model admitted she is trying to lose weight from her boobs after they grew to a 34FF.

Kelly, who described them as "the equivalent of three basketballs, explained how she puts weight on around her chest, and struggles to find sports bras to fit her figure.

She said: "I've gone up quite a lot. I was always booby but I have gone up quite a lot, I think I've gone up to a 34FF. So it's about a kilogram each."

Kelly is in a lot of pain due to the strain her breasts put on her back, and insisted while others may be jealous of her curves, she doesn't always see it as a positive.

She added: "Because I was born with them, I don't know any different and I would love to not have boobs and just be able to wear a lovely little top and do more sport, and not have back problems, and not have to worry about them sagging."

The star was advised to lose weight by her doctor, and she opened up on what measures she was taking to help herself.

She said: "If I strengthen my core, then it's going to support me a bit better."