Updated

For one night only, the Rolling Stones were an up-and-coming band again.

The legendary group rocked a small club in Los Angeles on Saturday night for a minuscule crowd compared to the thousands set to see them launch their "50 and Counting" anniversary tour a week later on May 3 at the Staples Center.

The band kicked off Saturday's hush-hush 90-minute concert at the Echoplex in the hip Echo Park neighborhood with "You Got Me Rocking" before catapulting into a mix of new and old material, as well as their bluesy covers of classics from Otis Redding ("That's How Strong My Love Is"), Chuck Berry ("Little Queenie") and The Temptations ("Just My Imagination").

"Welcome to Echo Park, a neighborhood that's always coming up -- and I'm glad you're here to welcome an up-and-coming band," lead singer Mick Jagger joked after the second song of the evening, "Respectable."

Despite clocking in several decades as a band, Jagger, drummer Charlie Watts and guitarists Keith Richards and Ronnie Wood showed no signs of slowing down Saturday.

Jagger, who promptly ditched a black-and-white track jacket emblazoned with the band's logo after the first few songs, worked the crowd into a sing-a-long frenzy with "Miss You," complete with a harmonica solo from the strutting frontman.

Tickets to the Echoplex concert were sold earlier in the day for $20 each -- a fraction of what tickets to the tour cost.

Hundreds of fans lined up outside the El Rey Theatre across town earlier Saturday for a chance to attend the spontaneous show. Buyers were limited to one ticket, and they were required to pay with cash, show a government-issued ID, wear a wristband with their name on it and be photographed. Their names were verified at the venue, which has a capacity of about 700.

Cameras and smartphones weren't allowed inside the Echoplex, which usually plays host to hipster bands and mash-up dance parties. The lack of personal recording devices made the Stones' performance feel even more exclusive and old school, freeing concertgoers' hands of the gizmos that have become commonplace at concerts nowadays, and further bonding the crowd, many of whom built up camaraderie during the confusing ticket lottery earlier in the day.

Toward the end of Saturday's show, the band was joined by former Stones guitarist Mick Taylor for their version of Robert Johnson's "Love in Vain," as well as "Midnight Rambler."

The band, which was backed by Darryl Jones on bass, Chuck Leavell on keys, Bobby Keys on sax and Bernard Fowler and Lisa Fischer as backup singers, encored with the hits "Brown Sugar" and "Jumpin' Jack Flash."

"(This is) the first show of the tour, probably the best one," Jagger said at the end of the 90-minute set.

Bruce Willis, Gwen Stefani and Skrillex were among the famous faces in the sold-out crowd.

Rumors of the surprise show spread across social networks last week after the band teased the appearance on their Twitter accounts. The dance-pop band New Build, which was originally scheduled to play the Echoplex on Saturday, was first to leak details about the performance.

"Our gig got shifted b/c the Rolling Stones are playing Echoplex," the band posted Friday on Twitter. They joked that they were looking forward to "having it out" with the Stones.

The Rolling Stones performed a few dates together in London, Brooklyn, N.Y., and Newark, N.J., last winter, but didn't announce a tour until earlier this month. They will play 17 dates in the United States but said they may add more down the line. The lowest price for tickets to the show at the Staples Center, which has a capacity of about 20,000, is $250.