S.O.D. "When" by The Kalin Twins
5/3/2016 Written by songwriter/musician Paul Evans and songwriter Jack Reardon, this 1958 Gold certified pop tune ranked #1 for five weeks a piece in the UK and the Netherlands. On the U.S. Billboard Hot 100, it topped out at #5. The English rock band Showaddywaddy took the song to #3 with their 1977 version. In 2004, Irish singer/songwriter and TV personality Daniel O'Donnell, made the song popular again.
Hal and Herbert Kalin made up the pop duo and were actually twins. With this song being their real only hit out of 13 singles, they are considered one-hit wonders. Of course that is always a matter of opinion when you consider the fans.