Kim Kardashian's trainer reveals which easy exercise will get you "ripped" in no time.

He's one of Hollywood's top trainers, working out A-listers from Kim Kardashian to Lady Gaga - Harley Pasternak has done it all.

Currently working on 'Revenge Body With Khloe Kardashian', Pasternak recommends all of his clients - and all of us - should get back to basics with this simple fitness habit that will get you into good shape in no time...

Walking.

Yes, his one piece of health advice won't cost you a thing!

"I tell my clients you're wasting your time and my time coming to work out if you're sedentary the rest of the time," he says.

"As we become more technologically savvy with every innovation, we move less and less."

So how many steps should you do a day?

Pasternak recommends the average person walk at least 12,000 steps a day to be in good shape.

If you want to be ripped, Pasternak says to shoot for 14,000 steps.