Which groups of singers have recorded "Smile"?

There is some sort of recording of Charlie Chaplin's song "Smile" that was made in the 1960s or 1970s, I think, and stayed on the charts for a while. It was recorded by a chorus or group of singers, not a single vocalist or band. It was in the style of the Mike Curb Congregation or something like that, although apparently MIke Curb never recorded it. Does anyone remember which group this was? No, it wasn't The Lettermen.