Folks who shelled out their life savings to attend the Rolling Stones' first concert in London on Sunday (Nov. 25) may have had an incredible time, but they're about to start complaining. Word is that Eric Clapton will be sitting in with the group for tomorrow night's show.

U.K. tabloid the Mirror is reporting that Clapton will be a special guest on 'Gimme Shelter.' Also joining the Stones for the song will be hitmaker Florence Welch of Florence + the Machine, who will recreate the "Rape, murder" section made famous on the original by the inimitable Merry Clayton. R&B star Mary J. Blige did the honors on Sunday, while Jeff Beck played guitar on 'I'm Going Down.'

"...Me and Mick are going to wing on over to London and jam with the Stones!"

- Jeff Spicoli, 'Fast Times at Ridgemont High'

Spicoli might never have gotten his wish in his drug-influenced dream, but the Stones have a long history of special guest stars at high-profile concerts. In addition to Blige and Beck, the band welcomed Bill Wyman and Mick Taylor back into the fold on Sunday. In 1989, they invited Axl Rose and Izzy Stradlin of Guns N' Roses onstage to perform 'Salt of the Earth' for a pay-per-view show in Atlantic City, N.J.

Tickets for tomorrow's show are sold out. Online scalpers are reportedly selling standing-room places for as much as £5,000 ($8,000).