大象传媒

This episode's six groups include an a cappella group from King's College London called All the King's Men, Polish jazz group Alle Choir, the London International Gospel Choir, female vocal soul group Songbird Sessions, Welsh choir Sgarmes, and the newly formed 4 Tune Tellers and Kimmy.

To progress, the groups must impress the panel of musical judges - the nation's favourite choirmaster Gareth Malone, former choirgirl-turned-international recording artist Kelis, and superstar guest judge singer-songwriter Bebe Rexha.

The programme opens with an epic musical mash-up, arranged by the series musical director Deke Sharon, who is the musical director on the Pitch Perfect movies.

Groups then go head to head in a series of knockout choral challenges. First they each perform their showstopper before battling it out with their opponent in a themed riff-off. The judges then decide which group goes through to the solo battles later on.

At the end of the programme only two groups will remain, where they must face the ultimate sing-off - the final battle. Here they share the same song, before superstar guest judge Bebe Rexha joins in with the group the judges have chosen to go through to the final.

Bebe Rexha will return in the grand final to sing with the show's winning group, who will be one step closer to the 拢50,000 cash prize.