by Susi May 9

I always thought three was the magic number, but for celeb trainer Harley Pasternak there is magic in the number five. His 5-Factor philosophy of diet and fitness has helped Hollywood darlings from Jessica Simpson and Eva Mendes get fit. Although he currently works with Vanessa Williams and Alicia Keys, Pasternak will be accompanying Lady Gaga on tour. He's bringing snacks as well as workouts to keep the diva in shape while on the road.

We know you're busy too, so we asked Harley to create a holiday time-saver workout for FitSugar readers. His 30-minute workout gets your heart rate up and works your legs and abs — two areas I always want to tone. To check out his workout keep reading.

Harley says, "Do all this workout without taking any rests . . . Look at it as very 5-Factor with (1) Cardio Warmup (2) Lunges (3) Deadlifts (4) Double Crunch (5) Cardio cool down. 5 Phases!!!"

I love the mixing cardio with strength training. Here are details on doing double crunches — the move toning Lady Gaga's middle — as well as deadlifts and walking lunges. For a printable version of the workout click here.

Source: Getty and WireImage