Kristin Cavallari 'Really Impressed' With Heidi Montag's Miss Universe Performance

'She looked like she'd put a lot of hard work into it, and it paid off,' 'Hills' star says.

Kristin Cavallari, who will join "The Hills" cast for the show's next season, has plenty of praise for castmate Heidi Montag's performance at the Miss Universe pageant on Sunday night.

"I was really impressed," Cavallari reportedly told UsMagazine.com at a Nylon magazine party in Los Angeles on Monday night. "It reminded me of Britney Spears at the VMAs — whatever year that was — when she ripped off her suit and was, like, nude with sparkles. She kind of looked like that."

Heidi's Miss Universe Pageant Dance Rehearsal

She's referring, of course, to Britney's 2000 performance of "Oops, I Did It Again" at the VMAs,

and Montag has spoken at length about her admiration for Britney. Montag's outfit for her performance of "Body Language," the first single from her self-titled album (due September 29), clearly showed that influence.

"She looked like she'd put a lot of hard work into it, and it paid off," Cavallari added.

While Montag got praise from Cavallari, sister-in-law Stephanie Pratt

and, of course, husband Spencer Pratt for her performance, not all of the comments were positive. But she said she doesn't care what people think.

"I think people don't know what to expect, and how can they?" she told The Associated Press before hitting the stage at the pageant. "It's my first performance live and it's in front of a billion eyes. So I'm very excited to show everyone what I'm coming with."

Afterward, she took to Twitter to talk about the performance, for which she wore nude-colored, sequined track pants and a matching bra that looked very similar to Britney Spears' 2000 Video Music Awards outfit. Backup dancers flanked Montag as she danced and lip-synched to "Body Language." "Last night was one of the best nights of my life!!!!" she wrote. "I had so much fun! my first performance! thank you God!"

In the hours leading up to the show, Heidi tweeted about being excited for the pageant: "All things are possible with God! dreams do come true! enjoy every moment of this short life!!"