The Vampire Diaries star Nina Dobrev (Elena) took to Instagram over the weekend, posting a video of her and Derek Hough breaking it down in the VIP section at the festival. Along with the clip, she wrote, "#2chains #lollapalooza this is insane !!! #amazing!"
As for why the Dancing With the Stars pro ended up chilling with Nina? She and Derek's sister Julianne are BFFs, so we're thinking it was just a platonic hangout.
Check out the video below to see Derek and Nina having fun during the performances, and then sound off in the comments!
Catch the Dancing With the Stars Season 17 premiere on Monday, September 16, 2013 at 8 p.m. ET/PT on ABC.