Adrian Grenier has signed on to sort of guest star on 90210. Allow us to explain...

The actor best known for playing Vincent Chase on HBO's Entourage will appear on the September 27 episode of the CW drama.

But he'll only appear in a musical context, as Grenier's real-life band, The Honey Brothers, will perform at Naomi's 18th birthday party. At the very least, fans can look forward to Naomi tossing a flirty line in the actor's direction.

90210 returns with new episodes on September 13. Watch a preview for the new season NOW.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.