ET was with "Dancing with the Stars" contestant Kendra Wilkinson as dance partner Louis Van Amstel put her through his rigorous dance class to get her ready for the show’s big premiere!Kendra said she thought her "DWTS" dance rehearsals were hard until she attended this fast-moving dance class. "Louis' dance class is way harder than dance rehearsal. I thought it was going to be a lot easier, but no - it's harder. I actually look like a rookie in here!" Louis agreed that his dance class at L.A.'s Crunch gym is hard work, but said it can be a lot more fun than other exercise. "I think dance is the best alternative to workout because you don't really feel you're working out. You're not on the treadmill, you're not on the elliptical, you're dancing to music. And the fact that you burn a heck load of calories, and you're dancing to your favorite music." (ETonline.com)