Here's a theory for you non-'80s fans out there: You would have no Paul Rudd to worship today without Paul Reiser's impact in the '80s.

For years actually, I confused the two comedic actors, because it almost seems like Reiser faded away from starring roles about the same time Rudd started to grab them for himself. Never mind that they share the same first names, hairstyles and nearly the same soft-sale touch on wit.

They also both play the same characters: A pleasant looking guy who's (usually) happily in love with a woman who's (usually) sane while still being the trusty (discreet) wingman to a saltier cast of guy friends.

Reiser made his mark back in 1982 with Diner (trailer), costarring a whole lot of other "weren't they so great back then" actors like Kevin Bacon, Mickey Rourke, Daniel Stern and Steve Guttenberg. People remember the popcorn bucket scene with Rourke, but what I took away from Diner were the zingers from Reiser. "You know what word I'm not comfortable with? Nuance. It's not a real word." And the brilliant ... "We all know most marriages depend on a firm grasp of football trivia."

Take either of those lines and drop them on Rudd's "David" character in 40-Year-Old Virgin. Seemless, right? They could be spoken with total believability by either actor.

After Diner and his tiny role as "Jeffrey," Axel Foley's Detroit sidekick in Beverly Hills Cop, Reiser didn't really find his niche until the late '80s and '90s, when he was all over the big screen and TV in My Two Dads (mini-sode), Mad About You, Aliens and Bye Bye Love. (trailer)

Today he's no doubt celebrating his 52nd birthday, but he seems to be taking a prolonged break from the movie biz. Maybe it's because Rudd and Reiser are the Superman and Clark Kent of comedy and can't be in the same place at the same time. 

Judd Apatow, do us all a favor. Cast them both in the same movie. Big brother, little brother. Whatever it takes. Time to find out which actor wears the cape.

FIVE MORE GREAT PAUL REISER LINES:

5."We can't level, you crazy bastard, we're in advertising!" (Crazy People)

4."You know what the odds are on that? Impossible to one." (The Marrying Man)

3. "It's a very awkward age for girls. ... 13 to 35, very awkward." (Bye Bye Love)

2. "This is not my office!" (Beverly Hills Cop II)

1. "This is not my locker!" (Beverly Hills Cop)