PHILADELPHIADemi Lovato and Miley Cyrus met on the set of "Hannah Montana" six years ago, long before they became two of the biggest names in pop music. Now, they're competitors at the 2013 Video Music Awards, and despite their very different lifestyles (Demi isn't much of a twerker), Lovato thinks their friendship will last.

"She knows how I feel about the whole partying thing," Lovato told MTV News. "I love her to death and I'm always like, 'Just be careful' and she's like, 'Dude, I'm chilling. It's fine.' But I care for her so much that I'm so protective, but she's good. She's got a good head on her shoulders."

Lovato and Cyrus are facing off in the Best Female Video category at the VMAs. Demi is nominated for her emotional power-pop hit "Heart Attack," while Miley is up for her laid-back party anthem "We Can't Stop."

"I think it's great," Demi said about her friend's latest hit. "I think it's a good song... It's a song a lot of people have fun to and if people are enjoying it, then great."

Just last year, Lovato told MTV News that she steers clear of the partying scene, saying, "I'm crazy with my hair... it's my only form of rebellion, I don't drink, I don't do drugs, I don't party." Cyrus, meanwhile, has been open about her "party animal" image.

Despite their differences, Lovato said she would "absolutely" be down for a collaboration, only if there isn't any twerking involved.

"She's twerking and she looks amazing doing it," Lovato said of Cyrus. "I don't want to do it in public. One, because people are going to be like, 'Oh, who twerks better?' And two, I'm really tired of the word 'twerking.' It's like 'swag', it's like, 'OK, just stop.' Or 'YOLO;' just don't."