Tickets are gone but -- hey! -- Britney Spears is playing a free concert at the Rain nightclub at Las Vegas' Palms Casino and Resort tonight. Starting on Wednesday, fans could sign up for tickets, though it wasn't revealed until today just where the show would take place.

The singer had alluded to the gig this week, the announcement popping up today on her Twitter account.

The special guest -- or just guest, should you not care for "Jersey Shore" -- is "DJ" Pauly D. MTV will be taping the event for a TV feature. Spears previously took the stage at the Rain back in 2003, for a suprise set in support of "In the Zone."

The gig comes this Friday before her new album "Femme Fatale" drops. We review it here.

Can't make it to the Strip tonight? Spears has announced a TV appearances on "Good Morning America" and "Jimmy Kimmel Live!" on release day, Tuesday (March 29).