Mumford and Sons aren't sure they can compete with The Rolling Stones at Glastonbury and admit the festival appearance is a big "risk."

The "I Will Wait" band see headlining the world renowned event as the biggest "gamble" they've ever taken, and aren't sure if they can live up to the legacy of their co-headliners - who have been touring for 50 years.

"It's a really huge deal to headline Glastonbury; we're a young band with only two records behind us. This summer is probably the biggest risk we've ever taken," frontman Marcus Mumford said.

Banjo player Winston Marshall added, "I've seen The Stones play for three hours and the crowd knew every song. It's what you want in a headline slot at a festival. I'm scared because it feels like a gamble. We don't know if we've earned it yet or not."

Bass player Ted Dwayne also admits he's getting nervous in the run up to their closing festival slot on Sunday June 30: "The other night was the first time I visualized the [main] Pyramid Stage in my head. I hadn't made that connection before, and it actually real, it's really, really scary."

However, the quartet - which also includes Ben Lovett - have promised a special show when they do set finally step out onto Glastonbury's famous stage in Somerset, South West England. "Once you're out there, in front of people, I don't think there's any choice than to just give it your all. The day we struggle to enjoy what we do and just get the gig over with we'll quit," Marshall said.