Selena Gomez Jams with FTSK

Selena Gomez high-fives lead singer Jonathan Cook as she plays a set with her favorite band FTSK at Avalon in Hollywood on Thursday evening (December 3).

FTSK just released their new album, This Weekend: Friday. Be sure to pick a copy up at their official website, ForeverTheSickestKids.com.

Also spotted out to support his “little sister” was David Henrie.

Also, check out Selena‘s concerts that were featured on Radio Disney: Total Access below! She did AMAZING!