Trio played second of three London gigs last night (May 15)
The band make live return ahead of much-anticipated new album
Sigur Ros, Justice, Hot Chip have also joined the festival's roster
The band hint the song will appear on their next album
'We're just about to start recording,' says Jamie xx
The London trio join Death Cab For Cutie and Spiritualized on the Spanish festival bill
Band also start a new blog to document the recording process
Beyonce's little sister is set to DJ at a pub in the capital
Producer passed on offer to work with Mike Skinner on latest album