Jennifer Lopez’s personal trainer has revealed exactly what type of work-out he will be giving the new mother to aid her weight loss after giving birth to twins.

Gunnar Peterson, body sculptor to the stars, told OK! that as soon as the doctor gives J-Lo the all-clear, they’ll be in the gym together. "We're already setting it up,” he said. “She's an organizer and a planner."

Jenny from the block will have a tough time ahead of her trying to get her slender figure back.

Peterson revealed he will "pay attention to her heart rate and start with light cardio and some body-weight exercises and build from there. Just like her kids will do in no time flat — it's walk before you run."

However, Peterson has no doubt about Jennifer getting back in shape. "This is not someone who dabbles in anything," he says with authority. "She's the last person I ever worry about getting back into shape."