Just watched this Soundie on YouTube. This classic song (the second movie tune to win the Oscar as it initially appeared in Goldiggers of 1935) is performed by the Mel-Tones with Mel Torme singing lead. Well, that may be his voice you hear but, according to the comments on YT, it's Bernie Parke lip-syncing to him since Torme had a previous engagement. Some comments also mention one of the female members as being Ginny O'Connor who later married Henry Mancini and another being Les Baxter who I'm guessing is the same one that composed many scores for American International pictures. Anyway, this was another "music video" from the '40s that originally played on Panorams (film jukeboxes) in restaurants, bars, and train or bus stations. Worth a look if you're interested in this sort of thing.