Joseph and the Amazing Technicolor Dreamcoat was a musical play.
When Melanie Bush first met the Sixth Doctor in Pease Pottage in 1987, she thought he was going to an audition for the musical. (AUDIO: The Wrong Doctors)
In an alternate timeline, Ace nicknamed the Sixth Doctor "Joseph" when she first saw him. The Doctor did not get the reference but Peri Brown found it amusing. (AUDIO: The Light at the End)