CHICAGO — For a band about to play the biggest show of their short career, Foster the People are pretty chill. An hour before they took the stage at Lollapalooza on Friday (August 5), the Los Angeles buzz band was feeling pretty pumped up about playing to the sweaty masses.

"I think we're all really looking forward to it," singer Mark Foster told MTV News. "I think today's gonna be the biggest crowd we've ever played in front of. This is our first major festival in the U.S. after our record's come out."

The VMA-nominated band's acclaimed debut, Torches — which spawned one of the buzziest tunes of the summer, the retro new-wave "Pumped Up Kicks" -- has only been in stores since late May, but Foster were confident their fans would be up to speed. "It's gonna be interesting to see people be familiar with all the songs and the deep album cuts."

And they were. Not only did they sing along to "Kicks," but the kids up front seemed to know just about all the songs, though a cover of Neil Young's "Heart of Gold" may have thrown them just a bit. Not only was it the first time People had played [article id="1668525"]Lolla[/article], but Foster said it was also his inaugural visit to the Chicago-based incarnation of the festival. Before he formed the group, he said he attended the last touring version of the alternative-music granddaddy in 2003, when it was headlined by Jane's Addiction, Audioslave and Incubus.

In addition to drawing energy from the crowd, drummer Mark Pontius said he was still pretty geeked about an inspirational tweet from a certain celebutante praising "Kicks." He was still feeling pretty good about the fact that none other than Paris Hilton had tweeted that she thought they were, well, "hot."

"I LOVE the song 'Pumped Up Kicks' by @FosterThePeople," Hilton gushed Monday. "So sexy! Puts me in the best mood, plus they are totally hot!"

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"Of course we were surprised about Paris Hilton tweeting about us," Pontius said, admitting something to the rest of his band. "Secretly, I don't know if I've ever told you, but I have a little bit of an infatuation with Paris Hilton."

Singer Foster laughed, "You're not the only one."

Pontius said he thought it was a good thing Hilton was tweeting about the band. "Maybe we can get married soon," he joked.

As for whether the stamp of approval had given them any added inspiration, Foster said, "Yeah, something like that."

MTV News is in Chicago for Lollapalooza 2011! Stick with us all weekend as we cover the bands you love and the bands you will love soon.