:dubious: Did you look at the second post in the thread (the very first reply to the OP)?
Christina Aquilara and Dee Snider.
This is what I immediately thought of. I thougt CK and JF were the same person, until I saw JF on The Concert for New York.
And then there’s Jerry Lewis and Jerry Lee Lewis…
Harlan Ellison and Larry Ellison.
Ron Perlman and Tom Waits
Another vote for Bill Pullman and Jeff Daniels. I’ve always mixed those 2 up.
Although they look nothing alike, Keith David and David Keith. And when I first saw the commercials for A Guy Thing, I thought Julia Stiles was Kirsten Dunst.
Russel Crowe
Sheryl Crowe
Cameron Crowe
The Crowes
The Black Crowes
(Are they all related, or what?)
Rocker
Chris Rock
“The Rock”
How am I supposed to tell all these people apart? Their names all merge into each other in my mind.
King Kong and Mighty Joe Young.
Kong was taller, though …
Also Lassie and Rin Tin Tin.
Although Lassie has longer hair and slightly larger breasts.
This thread would be incomplete if somebody didn’t mention Ino’s classic Pit rant about Jerry “Lee” Lewis. (You’ll need to scroll down to, like, the seventh object of his rage.)
Anyway, now somebody has.
For my part, I have the same Chris Rock/Tucker problem as Catcom; I can’t always keep John and William Hurt straight; and I gave up trying to tell the Baldwins apart ages ago, because, really, why bother?
For me, it’s always William Hurt and Jeff Bridges. I think they’re both terrific actors, but all I can remember is that Bill starred in Smoke while Jeff was - and always will be - the Dude.
HAHAHA… ow… that hurt… too funny… <gasp><pant><holds sides>
Ok… for me, are they really three different people or are Joey Lauren Adams, Renée Zellweger and Jewel really the same person?
“I had you at ‘You were meant for me’. You are such my bitch.”
Reuel
You know, he’s going to be in here any minute now to rip you a new one for misspelling his username. It’s actually lno with a lower case “l” and he is just a tad sensitive when it comes to this. 
Oh lno… calling lno…
And now that I mention it, I always get Ino and **lno[/] mixed up.
Like RickJay said, Lloyd Bridges and Leslie Neilsen are pretty much interchangeable as far as I’m concerned. But throw the guy who played the commissioner in Police Academy (I think his initials are G G) into the mix and I’m completely lost.
if I’m channel-surfing and suddenly
see one of these women talking
to a talk show host, I don’t know
whether I’m watching and listening
to Chita Riviera or Rita Moreno.
Although I have never had any difficulty telling them apart, my SO cannot tell the difference between Sandra Bullock and Julia Roberts.
and I know a lot of other people who have the same problem (I don’t get it…)
It must have something to do with their similar looks because it’s John Heard and William Hurt.
Soundwise, not necessarily looks-wise:
The singer from The Goo Goo Dolls and the singer from Matchbox 20. I’m sure they both have names.
Michelle Branch and Vanessa Carlton
Mandy Moore and Jessica Simpson.
MCA from The Beastie Boys and Zach dela Rocha from Rage Agaisnt The Machine