Sunday Night Trivia: Who Was Singin' In The Rain?

In the movie Singin' In The Rain (1952) Don Lockwood (Gene Kelly) and Lina Lamont (Jean Hagan) are the darlings of the silent silver screen. Offscreen, Don, aided by his happy-go-lucky friend and piano accompanist, Cosmo Brown (Donald O'Connor), has to dodge Lina's romantic overtures, especially when he falls for chorus girl Kathy Selden (Debbie Reynolds). With the advent of sound in motion pictures, it is decided to turn Don and Lina's new film into a "talkie" and a musical at that, The Dancing Cavalier. The only problem is Lina's voice, which mere words cannot describe. Thus, Kathy is brought on to dub her speaking and singing voice in secret, and Don's on top of the world. But then Lina finds out...Hilarity ensues.

For the movie in a movie, The Dancing Cavalier Debbie Reynolds dubs over Jean Hagan's singing voice and her spoken lines, but actually Debbie Reynolds only lip synched the words and song. Who actually provided the "voice" of Jean Hagan in The Dancing Cavalier?