AceShowbiz -

Khloe Kardashian and Mario Lopez have made their debut in "The X Factor (US)" season 2 as the competition kicked off its live shows. "No punching, no fighting, no screaming. OK, do, like, a little bit of screaming. I love screaming," the "Keeping Up with the Kardashians" star told the judges.

Donning a purple blouse with plunging V-neck, Khloe prompted Simon Cowell to say, "You're looking very sexy tonight. I think the air conditioning's on high tonight. It's very distracting." Mario surely had his own sex appeal as contestant Adam Brock asked, "Mario Lopez, can I pinch your butt?" after singing Jennifer Lopez's "Dance Again". The "Extra" host replied, "Oh! We gotta keep it PG-13 up here, buddy."

Demi Lovato, meanwhile, was seemingly smitten with Emblem3. "You boys make me swoon," she said after the group sang "One Day". She added, "I can't look you in the eye when you sing to me because I'm supposed to be a judge and not, um, you know, flirting with you while you sing... But I love you boys. You're so talented!"

Emblem3 also got praises from the other judges as L.A. Reid declared, "We have just witnessed America's next pop sensation." Britney Spears chimed in, "Your trio is amazing. You are absolutely adorable," and Simon even gave them a standing ovation.

Also delivering impressive performances that night were Jennel Garcia from Young Adults who sang Motley Crue's "Home Sweet Home", Arin Ray from Teens who performed Diana Ross' "You Keep Me Hangin' On", and Tate Stevens from Over 25s who delivered a beautiful rendition of Craig Morgan's "Tough".