The initial commenter wondered if Janet Leigh was dubbed in this film since he couldn't remember her singing in any of her other pictures. Well, she did sing in other films, most notably in "Bye Bye Birdie", and "My Sister Eileen", and while she was not known as an accomplished singer or dancer, she managed to give fairly good performances in both films and to demonstrate a competent ability in numerous guest appearances on variety television programs of the '50's and the '60's. I hope this will help to answer your questions. You might also look at her work in "Rogue Cop", where she plays a singer, and "Walking my Baby Back Home", a musical she made with Donald O'Connor, as well as "Fearless Fagan" where again, she is a singer/entertainer. She speaks at length about her musical experiences in her autobiography, "There really was a Hollywood", and gives a great accounting of her early career.