Lady Gaga's fitness trainer knew he had a challenge on his hands when he first met his quirky client - the pop star was playing basketball in high heels.

The pop superstar approached celebrity fitness guru Harley Pasternak last year to tone up her body in preparation for her exhausting The Monster Ball tour.

But he got a shock when he turned up to train the kooky singer and saw she was wearing a very unsuitable outfit for the gym.

He tells Britain's Heat magazine, "She came to me because she wanted to find a lifestyle that was healthy and something she could handle while she was on the road. I'll never forget the time I looked out of office door and there was was. She was dressed in a pair of 12-inch heeled boots, shooting basketball hoops."

Pasternak also learned that Gaga has a sweet tooth - so he created a line of healthy snacks to mail to the star while she travels the world.

He adds, "She loves potato chips and peanut butter so I was inspired to create a line of potato chips and peanut butter bars that we ship to her wherever she goes."