Mumford And Sons joined on stage by Nutini, Wolfmother and The Kooks

The 'supergroup' cover The Band's 'The Weight' onstage in Switzerland

Mumford and Sons treated fans at a Swiss festival to a surprise collaboration with Paolo Nutini, Wolfmother and The Kooks this weekend.

The quartet, who headlined the final evening (July 1) at the Open Air St Gallen in Switzerland, were joined on stage by the ‘supergroup’ to cover The Band’s ‘The Weight’ as a final encore to the three-day festival – scroll down to watch it.

Last week (June 27), Mumford and Sons posted a cryptic trailer for their forthcoming second album on their website. The clip – titled The Troubled Boys School, was possibly a hint at the title of the follow-up to their debut ‘Sigh No More’.

The album is due for release on September 24 and is set to feature ‘Below My Feet’, ‘Whispers In The Dark’, ‘Ghosts That We Knew’ and ‘Lover’s Eyes’.

Mumford and Sons frontman Marcus Mumford recently broke his hand. The band are currently playing their European festival shows with two extra musicians filling in for him on guitar and drums.

Mumford and Sons will release their tour film Big Easy Express on DVD on July 24. The film is available now on iTunes.

Watch fan-filmed footage of ‘The Weight’ below:

Watch Mumford And Son’s album trailer below: