Becky Stark and John C. Reilly, musical friends.

You know Lavender Diamond, right? The whimsical LA-based electro-folk band fronted by crystal-clear vocalist/tree fairy Becky Stark? The group plays SF's newest venue, the Chapel, Tues/11. Turns out, there's a super-secret surprise guest set to appear, and I've got a solid guess now we can announce who it is: John C. Reilly.

The rumored surprise guest (Reilly) is, of course, best known as the curly-haired character actor with a wide range (Magnolia to Tim and Eric Awesome Show Great Job!, Boogie Nights to Chicago to Step-Brothers). But he's also a pretty solid singer and musician, who played Bimbo's earlier this year alongside Lavender Diamond's Stark as John Reilly and Friends.

The duo previously collaborated on a duet covering  “I'll Be There (If You Ever Want Me),” made famous by Ray Price, for Jack White's Third Man Records, and have played together since. Reilly and Friends also popped up at Hardly Strictly Bluegrass this year.

If you hadn't already guessed, we're big fans of the actor-musician.

But we're also fans of Lavender Diamond, so either way, the show should be a good one. The band released its second full-length, Incorruptible Heart, in September, and a small batch was pressed on lavender vinyl. Amazing. It's a lush break-up record full of subtle melancholy, torch songs, and chamber pop, with contributions from M. Ward and the Calder Quartet on strings.

Plus, local wonder Jessica Pratt was recently added to the bill.

Alright, here's one more of Stark and John C. Reilly together from when Reilly recently stopped by Stark's web series, We Can Do It.

Again, it's rumored he'll show up. Oh, he'll be there!

Lavender Diamond
With Jessica Pratt
Tue/11, 9pm, $10-$12
Chapel
777 Valencia, SF
www.thechapelsf.com