Tom Cruise and Tom Kruse.
I had exactly the same experience with a coworker named Carmen Miranda. I asked him whether he ever goes around with a pile of fruit on his head. He didn’t have a clue. I’m at a total loss as to why nobody had ever mentioned this to him.
SNL had Joe Mantegna’s opening monologue get ‘interrupted’ by a disappointed son and dad who shuffled out upon realizing Joe Montana wasn’t hosting…
There was a brief news article in the newspaper a couple of years ago about Jerry Lewis, but the file photo accompanying the article was of Jerry Lee Lewis. 
They printed a correction a couple of days later. I’m sure they got a ton of emails about that one.
Paul Simon, the late bowtie-wearing senator from Illinois who ran for Prez in '88, was not easily confused with Art Garfunkel’s singing partner.
In a similar vein, 1980 POTUS candidate John Anderson would not be confused with Yes lead singer Jon Anderson
There is also a Heather Graham author and a Heather Graham actress whom I’m fairly sure are different people.
John “Hannibal” Smith is not typically confused with John Smith of Pocahontas fame or Johnny Smith from “The Dead Zone.”
He has, however, been interrogated regarding his frequent motel visits.
There was that embarassing occasion when they both showed up to host Saturday Night Live.
But that one’s cheating. Steven Anderson changed his last name to Austin when he started wrestling because of the TV character.
I don’t think Brian Peppers is ever going to get confused for someone else:
ABC’s Robin Roberts and baseball Hall of Famer Robin Roberts.
Ex-San Francisco 49er Roger Craig and ex-San Francisco Giant manager Roger Craig.
On a scale of 1 to 10, how likely is it for John McLaughlin the host to be confused with John McLaughlin who jammed with Miles Davis and Carlos Santana? (Odd that the “The McLaughlin Group” is not musical, though).
Eva Longoria and Evan Longoria.
Brett Butler and Brett Butler.
And neither of them are likely to be confused with Joe Nacchio.
Bond girl, and Medicine Woman Jane Seymour, I don’t think, is often confused with Queen Consort Jane Seymour third wife of King Henry VIII and succesor to Anne Boleyn.
Perhaps they’ll appear at Past-O-Rama in a Disco Dancing Contest with Einstein and Hammurabi?
My nominations: Captain James Cook and Captain James Kirk. 
Saddam Hussein (ex dictator of Iraq and ex dictator) and Nasser Hussein (ex England cricket captain).