Tonight he mentors another four a cappella choirs and gives them access to some of the best vocal tutors around to see what they're really capable of.
We've got a mature group called Yesteryear, a teenage combo known as Flight Of The Phoenix, a male barbershop outfit, and a Glasgow University choir all competing tonight. Who will be triumphant at the episode's end?
The Naked Choir With Gareth Malone, BBC2, 9pm
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