Earlier today Radio One hosted Mumford & Sons for a special live lounge session in which they played some songs off of their recently released album, Babel, along with fan favourites from Sigh No More. As well as these though they threw in a mystery cover of their choosing. They decided to have a go at Alt-J's stunning track "Tessellate" which features on, An Awesome Wave, also recently released Stateside. The result is a pretty darn great sounding version of the track that doesn't detract too far from the original. Mumford do however manage to weave in their own sound to the song marvelously. Check it out below.