If you think you don’t know what a counter-tenor sounds like, then here are a few names from the pop world: the Bee Gees, Smokey Robinson and the late Demis Roussos. The big names in classical - or more often Baroque - counter-tenor singing include Alfred Deller, James Bowman, Michael Chance and Andreas Scholl.
Joining their ranks now is Iestyn Davies, who joins Catherine Bott to talk about his voice, his career, his favourite music - and an extraordinarily busy year ahead, including a run in Handel's Saul at Glyndebourne.
Davies won the 2014 Gramophone Award in the Recital category for his album, Arise, my muse', a recording of a live performance he gave at London's Wigmore Hall. And he's shortly about to start a run in a new play at the Globe Theatre’s candlelit Sam Wanamaker Playhouse, playing one of the most famous singers of the 18th century – the great castrato, Farinelli.