I was listening to 60's music on Youtube the other day (I think you oldsters call it a "nostalgia trip"), listening to the music and then looking up the groups on Wikipedia. This song, and the group, "The Cyrkle", had a remarkable amount of musical horsepower behind them, considering the song was indeed "bubblegum" and the band started out as a group of college buddies. The song was written by Paul Simon, of Simon and Garfunkel, and given by him to the group, and the Beatles, including John Lennon and Brian Epstein, the Beatles' manager, were involved with the group's management and promotion.
I guess the pop music business in the 60s was a pretty small world; many of the groups that had hits in those days were related in some way.