Watch: Alt-J perform 'Breezeblocks' at Radio 1's Big Weekend.

Alt-J was one of the big names that performed at BBC Radio 1's Big Weekend music festival, performing hits like 'Tessellate' and 'Left Hand Free'. The English band closed out their set, however, with 'Breezeblocks' - which was a crowd favourite as they sang every single lyric back to them and danced to their hearts' content. 

Watch for yourself below as Alt-J performs 'Breezeblocks'...