Who is the male singer of WHEN I GROW TOO OLD TO DREAM?

Novarro and Laye go to a restaurant about 42 min into the film, and during the course of their visit a baritone sings "When I Grow Too Old to Dream" in the background. Novarro and Laye take their turns singing bits and pieces of the Romberg-Hammerstein classic song, but the tall, mustached, male figure in the background performs most of the vocal although he is broken up by movie scenes. The IMDB does not identify the singer, and the cast list does not help either. Credit should be given since it is due.