Sing: Ultimate A Cappella - Episode Guide

With no backing tracks, no instruments and no second chances, five groups hit the stage in a battle to become ultimate a cappella champions. Cat Deeley hosts.

The next set of groups bid to become ultimate a cappella champions, putting their spin on Bruno Mars's biggest hits. Cat Deeley hosts and Imelda May performs.

Cat Deeley hosts as the next five groups vie for a place in the final. They put their spin on Rihanna's hits. Plus, there's a performance from Reggie Watts.

The singing smackdown continues with five more groups going head to head. There are some incredible spins on Beyonce's biggest hits and JP Cooper performs.

Cat Deeley hosts as another coveted place in the final comes up for grabs and five more of the UK's best a cappella groups hit the stage. Midge Ure performs.

Cat Deeley hosts as the last five groups compete for the one remaining place in the final, putting their spin on One Direction's hits. Gregory Porter performs.

It's final time and one group are about to be crowned Sing: Ultimate A Cappella champions. Cat Deeley hosts as our six finalists battle to bring the house down.