I just found out that the future Joker, Joaquin Phoenix previously appeared on season 1 episode 20 of the Superboy TV Series. (which is available here on DCU if anyone didn’t know)
He played a boy genius who befriends Superboy/Clark and even donned a Superboy suit in a dream sequence. It was season 1 of Superboy so not a stellar episode, but still cool to know he had that kind of ties to DC Comics adaptions before. Starting to thinke veryone was on a DC TV show/Movie at some point.