Fans who attended the Anaheim, Calif. date of the Rolling Stones' '50 & Counting' Tour' got a little bit more than they bargained for Saturday night (May 18). Former Nirvana drummer and Foo Fighters front man Dave Grohl came out mid-set at the Honda Center to join the legendary rockers for a searing rendition of 'Bitch.'

It wasn't a last-minute jam; the Stones teased Grohl's appearance via Twitter earlier Saturday. Clad in his usual post-grunge attire of plaid shirt and jeans, a joyous Grohl banged out the guitar parts along with Keith Richards and traded vocals with Mick Jagger in what must have seemed like an impossible rock and roll dream come true.

The set proved there's still life in the band; unlike some of their more bloated past tours, the Stones sounded rawer, more stripped-down, lean and mean on Saturday night. Former Stones guitarist Mick Taylor also joined the band for 'Midnight Rambler' and '(I Can't Get No) Satisfaction).'

The group's current tour has provided plenty of surprises for fans. Gwen Stefani and Keith Urban were onstage on opening night in Los Angeles, while Tom Waits, John Fogerty and Katy Perry have also jumped onstage at various dates.

As for Grohl, he's starting to make a habit out of jamming with legends; he recently said that inducting Rush into the Rock and Roll Hall of Fame and jamming with them at the induction ceremony was "one of the most special nights of my life."

The Rolling Stones will perform at the Staples Canter in Los Angeles on Monday (May 20) before heading to Toronto for a gig next Saturday (May 25).