Try listening without singing along. I dare you.
[...] King had no intention of recording the song himself when he wrote it. King had written the song for The Drifters, who passed on the chance to record it. It was not until after the Spanish Harlem recording session that he had some studio time left over. The session's producers, Jerry Leiber and Mike Stoller, asked if he had any more songs and King played "Stand by Me" on the piano for them. They liked it and called all the studio musicians back in to record it. If King hadn't finished recording his other songs early, "Stand by Me" may never have been recorded.
Thanks to Misty.