The song was done first by a group called Sonny Dae and the Knights. It was then covered by Bill Haley and the Comets. Initially, the Haley version was not a hit, but when it was included in the soundtrack for the hit Glenn Ford film Blackboard Jungle, "Rock around the Clock" became a sensation and zoomed to #1 on the charts where it stayed for two months. Its reign at the top began this day in 1955. It was the first true rock and roll single to reach #1. It was later used as the theme song for the early episodes of TV's long-running Happy Days.