The Sound of Music was a film starring Julie Andrews.
Disguised as a "Sister Cantica", River Song noted that she must have looked like an extra from The Sound of Music to Helen Sinclair. When Helen expressed unfamiliarity, River remembered that, being from 1963, she would not have seen it yet. (AUDIO: The Doomsday Chronometer)
Sylvia Gribbins thought that St Agnes Abbey was "a long way off anything in The Sound of Music" and the nuns didn't remind her much of Julie Andrews, either. (PROSE: Eye of the Gorgon)
The Fifth Doctor saw The Sound of Music at Christmas on TV. (PROSE: In the TARDIS: Christmas Day)
Behind the scenes Edit
According to Russell T Davies, David Tennant went to the theatre with Kylie Minogue, to see The Sound of Music. He wondered why this didn't make the tabloids. (REF: The Writer's Tale)