Preview: Tower Festival, Tower Of London, London

Cullum plans big surprise for festival-goers

Jamie Cullum has something special in store for his only London performance of the year. "We've got a phenomenal surprise planned," he says cryptically. "It's the kind of surprise that is never likely to happen at one of my shows ever again."

Though the singer is keeping tight-lipped about exactly what this surprise involves, he assures it will make the night one to remember. "For sheer spectacle and music, it's going to be really amazing," he enthuses. "It's too over the top and expensive, but we're going to do it anyway."

Part of the reason for Cullum going the extra mile this time round is the quality of the festival's line-up.

James Brown, Dionne Warwick, Pet Shop Boys and Jeff Beck and Buddy Guy are just some of the big-name artists who are scheduled to appear over several nights. "It's an absolutely extraordinary line-up," says Cullum, who is currently on a world tour in support of last year's Catching Tales album. "It makes me rise to the challenge."

Now in its second year, The Tower Music Festival gives music fans the opportunity to watch their favourite acts at a World Heritage Site, putting a pleasing twist on the usual gig-going experience. "I've played a lot of the traditional venues in London, like the Hammersmith Apollo and the Royal Albert Hall, and they've all been incredible," Cullum says. "But I think the opportunity to play a non-concert venue will be really fun."

The concerts will be held in the moat, with ticket-holders invited to picnic on its lawns prior to the performances, which also include sets by Dr John and Randy Newman, Madeleine Peyroux, Pink Martini and Al Jarreau.

"I'd like to see James Brown, and it would be extraordinary to see Dionne Warwick," says Cullum. "It's stupid to miss people like that, because you never know how many more shows they're going to do."

28 June to 14 July (0871 230 9855; www.towermusicfestival.co.uk)