This one is about recognizing someone from a kids’ show (Saturday morning, ideally) turning up in a “real” (Prime Time, ideally) program.
For example, when “The Love Boat” started, I recognized Gopher (Fred Grandy) as being “that guy from Monster Squad” (Monster Squad - Wikipedia) - a program about the night watchman at a wax museum who helped the wax versions of classic monsters to fight crime.
Morgan Freeman. I first knew him from being in the cast of the PBS educational series The Electric Company in the early 1970s, when I was a little kid. Then, in the late '80s and early '90s, he finally started getting big movie roles, but I kept thinking about him as Easy Reader, his Electric Company character, and asking “What about Naomi?”
Not quite the same maybe, but I remember reading Robert Reed was sorely put out that he would probably forever be known as Mr. Brady on The Brady Bunch and not as the serious actor he considered himself.
A behind-the-scenes example from The Electric Company; the show creator and head writer was Paul Dooley, the actor who was the father in Sixteen Candles and Breaking Away.
Paul Dooley! I may remember him from “A Mighty Wind” and from being one of the more peculiar judges on “The Practice.”
Another example. I was watching “Sleeper” some years back and one guy looked very familiar - because he was Spencer Milligan - Rick Marshall of “The Land of the Lost.”
Pee Wee’s Playhouse, which is considered a cult show for adults now, did run (1986-90) on CBS’s Saturday morning kids’ shows line-up. And of course it featured early roles for Laurence Fishburne, Phil Hartman, and Law and Order’s S. Epatha Merkerson.
Another kind of opposite: Tim Matheson from TV and movies and National Lampoon magazine was the original voice of Jonny Quest – his name was spelled differently.
I did the same thing back when ST:TNG originally aired.
Come to think of it, I think that was the first time I realized actors could play more than one role. I was old enough to understand that the people on TV were actors, but I think I thought the actors on TV just played the same part their entire career. When I saw the guy from Reading Rainbow on Star Trek it clicked that actors can be in more than one show and play more than just one role.
I think you can figure out approximately how old someone is by whether they think of LeVar Burton as the guy from Roots, the guy from Reading Rainbow, or Geordi from Star Trek, The Next Generation.