It had been at least ten years since I first heard THE HOLLIES-"LONG COOL WOMAN (IN A BLACK DRESS) W/LYRICS before I was informed that it wasn’t by Creedence Clearwater Revival!
Share your “Wrong Artist” malfunctions, if you dare.
“Taking Care of Business”
As God is my witness, I thought it was by the Doobie Brothers. For my entire life, until three years ago, I never knew it was actually Bachman-Turner Overdrive.
Back in the early days of Elvis (Heartbreak Hotel early) I really liked his sound (who didn’t?) but I found it difficult to keep his sound separate from Roy Orbison-Ooby Dooby or Gene Vincent - Be-Bop-A-Lula and a few others. Of course, that didn’t take too long to fix!
When The Moody Blues’ Gemini Dream came out in '81, I was certain it was a new single by the Electric Light Orchestra. (Both were synth-heavy prog-pop bands from Birmingham, so maybe it’s excusable. 
)
I’ll confess: I thought Do It Again was by Santana, not Steely Dan, until sometime last year when my husband cleared up my confusion.
Stone Temple Pilots have the dubious distinction of having a couple of songs that fit the bill.
Plush is a Pearl Jam ripoff, and so is Creep, with a side of Nirvana-aping in the chorus.
I thought Joe Dowell’s “Wooden Heart” was Elvis. Same with Terry Stafford’s “Suspicion.”
In a somewhat related vein, a DJ once accidentally played an lp (33rpm) version of “Imaginary Lover” by The Atlanta Rhythm Section at 45 rpm, and lead singer Robert Nix, sounded a lot like Stevie Nicks.
That had to be a hoot! I love ARS and Buddy Buie’s songs.
I thought for the longest that "Mary’s Prayer"was by Steely Dan. I remember searching to find what album it was on, obviously to no avail.
I also thought " I Love you Always Forever" by the annoying Donna Lewis was by the annoying Sophie B. Hawkins.
I always thought “Turn the Page” was by Metallica. It turns out that they did do a cover of it (that was one of their biggest mainstream hits) in 1998. But I recently found out that the live, soulful version you usually hear on the radio is the original, by Bob Seeger, back in 1976…
Until just a couple of years ago, I thought “Who Loves You” was by The Doobie Brothers…sounds a LOT like something they would have gone.
Also thought that “How Long” was by Steely Dan…after all, it sounds boring enough…
And the first time I heard “One Bad Apple,” I thought it was a Jackson Five song I somehow never heard.
“Stuck in the Middle with You” is so totally the Beatles. I mean, that’s absolutely John singing!
Except it’s not. Never has been. It’s Stealer’s Wheel.
I recently re-watched The Big Lebowski and the wonderful dream sequence with the song, Just Dropped In (To see what condition my condition was in).
I had assumed the song was by a hard rock band and I wanted it on my Ipod. Who sings it?
Kenny Rogers. And the First Edition. Really, Kenny Rogers?
Me, about 10 years ago: Bro, have you heard anything by Citizen King, they do “Better Days”, that song that sounds a little like Beck.
Bro: Wait, that’s not Beck?
I thought “Lonely Days, Lonely Nights” was a Beatles song Nope: It’s the BeeGees!
Yeah but they’ve been accused of that their whole career. See also, Muse and Radiohead, at least on their earlier albums.
I thought “Dream On” by Aerosmith was by Led Zeppelin or solo Robert Plant or something. I was confused by the screechy vocals, and the fact that it didn’t completely suck.
I thought “Don’t You Evah” by Spoon was Beck.
Thanks to early exposure to the Muppet Show, I spent YEARS thinking “Just An Old-Fashioned Love Song” was actually recorded by Paul Williams instead of Three Dog Night.
And I’m still mightily confused about which 70s releases were by Paul McCartney and which were by Paul McCartney and Wings.
Isn’t Creep by Radiohead?
You’re thinking of the “I’m a creep, i’m a weirdo” Creep. STP did the “takes time with a wounded hand, cause he likes to heal” Creep.