Rosie Huntington-Whiteley has three personal trainers.
The British beauty - who is the face of Burberry Body - admits she needs to always be in the gym to maintain her trim physique, and has trainers in all three cities in which she works.
She said: "It takes lots and lots of hard work. I have three personal trainers - James Duigan in London, Jason Walsh in Los Angeles and my friend Justin in New York. That means there's no excuse not to be in the gym wherever I go."
In addition to a strict exercise regime, the 24-year-old model also controls what she eats, and tries to put few carbohydrates into her body.
She added to Britain's Grazia magazine: "Everything starts with exercise. Then you want to look after yourself and put good food in your body.
"I have a really good response when I cut out carbs so that's something I always do before a great event. I eat a high-protein diet and lots of greens."