Thunder have been forced to sideline guitarist Ben Matthews for their appearance at the Calling festival in London this weekend.

He's had his tonsils removed and won't be well enough to perform – so the band have brought in Peter Shoulder of Luke Morley's other band The Union, to stand in.

Frontman Danny Bowes says in a statement: "Ben is unable to go out or sing, so he cannot do the show on Saturday at Clapham. Rather than cancel, the band has asked our good friend Peter Shoulder to play guitar, and he has agreed to step in.

"Ben is currently advising Pete (via text) on hair tips and shape chucking. In return Pete has agreed not to sing and play too well. Please join us in wishing Ben a speedy recovery, and thanking Pete for saving the proverbial bacon."

Thunder recently announced they were planning to record an album, despite having previously said 2008's Bang! would be their last.

The Calling festival on Clapham Common features Aerosmith, Joe Bonamassa, Richie Sambora, Walking Papers and others on June 28, while the following day's event is headlined by Stevie Wonder.