Mumford and Sons will perform a free gig to celebrate the release of a new documentary about the band.
the gig, at the SXSW festival in Texas, will see the Mumfords take to the stage with Edward Sharpe And The Magnetic Zeroes and Old Crow Medicine Show on 17 March, following the premiere of Big Easy Express.
The film documents the band's Railroad Revival Tour of the US, where they boarded a 1940's train, stopping off to play gigs between San Fransisco and New Orleans.
SXSW is one of the world's leading music conferences.
Watch the trailer for Big Easy Express below.
