Complex sentence: In the original London Cast, Mistoffelees also sings "The Old Gumbie Cat"; in the original Broadway production, he sang "Mungojerrie and Rumpleteazer" until the song was reworked to allow those two characters to sing it.
Split into simpler sentences: In the original London Cast, Mistoffelees also sang "The Old Gumbie Cat"; and in the original Broadway production, he sang "Mungojerrie and Rumpleteazer". However, the song was reworked to allow those two characters to sing it.