Halle Berry keeps in shape by working out "four muscles at once".
The Oscar-winning actress is well known for her slim frame and killer curves.
However, her trainer Nat Bardonnet has revealed that it takes a lot of work to get Halle’s enviable physique.
"If we can work four muscles at once, we're going to!" Nat told Us Weekly.
One of their favourite moves is a cycle of quick squats with arm raises. Nat believes the move is great for working on all of Halle’s problem areas.
“You work the thighs, butt, biceps and core!" she revealed.
The actress also has to give her body enough energy to get her through the intense hour-long, four-day-a-week workouts with Nat.
Halle likes to refuel with protein shakes from West Hollywood's Earth Bar and "she also eats energy bars," Nat added.
As well as looking after her appearance, the stunning star also concentrates on her health. Halle suffers from diabetes so she grazes regularly throughout the day to keep her blood sugar level and metabolism up. She prefers to stick to healthy snacks such as fish, salad and soup.