Bill Hayes was a singer and actor known for his appearances on the show. He was popular for his romantic ballads and comedic skits. However, he wasn't a "singer" in the sense of being the show's primary musical act, as that role was filled by other performers like Julius LaRosa.
Unfortunately, Bill Hayes passed away in 2010.
It's possible you are thinking of someone else, in which case, please provide more details about the person you are looking for.