This thread is similar to songs that sound like different act, but it has more to do with different singers/groups etc. that could have been mistaken for another act who had hit(s) around the same time. To start off, I ran across a couple that have been on my mind;
From 1981- Robbie Patton's "Don't Give It Up" could have been mistaken for a follow up single to Rick Springfield's "Jessie's Girl"
From 1982- Tane Cain's "Holding On" could have been mistaken as the new/follow up single from Quarterflash who had two hits from earlier that year "Harden My Heart" and "Find Another Fool"-I think that Tane Cain sounded a lot like Rindy Ross of Quarterflash.
^One song that comes to mind is Julian Lennon's "Valotte". When that song came out in late 1984, it was just a few months after the posthumously released hit "Nobody Told Me" by Julian's father. At the time, I thought it was a follow up to John's "Nobody Told Me" rather than his son's debut hit. "Valotte" easily sounded like it could have been sung by John.
To me, the ultimate example of this phenomenon occurred in the summer of '85, when I first started hearing a certain funky number on the radio titled "Oh, Sheila". I was so sure that it was the latest Prince release--until I started to hear another funky number, "Pop Life". My confusion cleared up soon enough when I learned the latter song was the "Raspberry Beret" followup, and the former was by a new, soundalike group known as Ready For The World. (BTW, have you ever noticed that the other charttopping song in the rock era with Sheila in the title, the Tommy Roe song from 1962, was also a soundalike song; in this case, a dead ringer for a lost Buddy Holly recording.)
"Who do you love?"---Bo Diddley
"Swear allegiance to the flag, whatever flag they offer. Never hint at what you really feel."---Mike and the Mechanics