Countertenor

A countertenor -- or, as perhaps wrongly credited in The End of Time, counter tenor -- is a male singer whose vocal range is roughly that of a female or. Effectively, this makes a countertenor a type of adult male.

The only known credited countertenor in Doctor Who history is Mark Chambers, who famously sang "Vale Decem" over the concluding moments of David Tennant's regular run as the Tenth Doctor. Chambers was also present for a live rendering of the piece at the 2010 Proms event.