While Chrissy Teigen and LL Cool J host Lip Sync Battle, the true star behind the scenes is Teigen's daughter, Luna.

During a recent visit to the set of the Spike show, ET found out that Teigen's 6-month-old baby with husband John Legend is a frequent visitor to the set. Naturally, Luna is a huge attention draw, but she seems unfazed by it all.

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"She really is pretty indifferent," Teigen told ET with a laugh. "She has the same routine: sleep, eat, nap, sleep, eat, nap. It never changes no matter where we are, but she does like to see her Uncle Todd."

Uncle Todd is LL Cool J (real name James Todd Smith), and the feeling is mutual.

"She likes Uncle Todd," LL said through a big smile.

Legend is also a regular VIP guest backstage at Lip Sync Battle, and has even given an impromptu performance.

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"My man John Legend has sung 'Happy Birthday' on this piano," LL told ET backstage.

Between the celebrity sightings and the décor, the Lip Sync Battle set is quickly becoming the hottest hangout spot in Hollywood. The massive set includes two soundstages, a pool table and a piano bar.

"When the acts are getting ready and want to go and have a drink, if they want to relax and have a cocktail or whatever, they can be here," LL said.

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The new digs are for the show's upcoming third season, which will feature appearances by Sir Ben Kingsley, Jay Leno, Wanda Sykes, America Ferrera and more.

Lip Sync Battle returns to Spike on Oct. 12 at 9 p.m. ET/PT.