From Jillian Michaels to Zac Efron: See the Celebs With Hollywood's Hottest Abs!

Find out which stars have the best abs in the business

Celebrities have some of the best bodies in the world!

Stars want to look and feel their best in movies, on TV and in photos, so they train around the clock to whip their bodies into shape.

Everyone from Jillian Michaels and Zac Efron to Kourtney Kardashian and Kylie Jenner have incredible abs. How do we know this? Well because we have the photos to prove it!

In celebration of the upcoming premiere of Jillian's E! show Just Jillian, we wanted to take a look at the celebs with the best abs in the business, just like Jillian.

Check out the gallery to see celebs with Hollywood's hottest abs!

Watch the premiere of Just Jillian Tuesday, Jan. 19 at 10 p.m., only on E!