#2 Andre The Giant in The Six Million Dollar Man (1976)
While Andre The Giant will go as one of the most legendary professional wrestlers in the 20th century, The 8th Wonder of the World did have some acting credits to his name. His most famous role was in The Princess Bride (1987), he was the go-to "star" for characters that demanded a larger-than-life presence. The former WWE Superstar was a guest star in the popular 70s television show, The Six Million Dollar Man.
He played the fabled Bigfoot character in a 2-parter episode called The Secret of Bigfoot.
If people are unaware of the show, it starred Lee Majors as Col. Steve Austin (ironically) who was put back together after a near-fatal test crash. His arms and limbs are replaced by Bionic implants, which invariably have greater strength and speed. For all intents and purposes, he is a Cyborg.
It's safe to say that Andre The Giant doesn't fare well one-on-one with Steve Austin. Perhaps in WWE, he would have been booked differently.
#1 Lex Luger in Superboy (1990)
Believe it or not, Lex Luger was not only a make-believe superhero in WWE, he also happened to guest star in the forgotten TV series, Superboy. The show lasted four seasons and was essentially Superman in his teen years. Mostly, it's like Smallville but with lesser WWE Superstars.
Interestingly, Lex Luger, who was The Narcissist, Made in the USA and The All-American in WWE and The Total Package in WCW, actually got the chance to put on the fabled costume with the most recognized superhero symbol there was.
While he plays Superboy Mark II, it's probably fair to say that his body physique didn't need to be altered to fit into that costume. This role remains one of Lex Luger's known acting roles to date, though it's possible that there were other acting roles that WWE fans haven't seen yet.
It should be noted that Lex Luger was in WCW at this point of his career and hadn't made it to the WWE as of yet. Luger remains one of the few WCW World Champions never to win a title in the WWE. However, he did co-win the WWE Royal Rumble match in 1994 alongside Bret Hart.
When WWE brought WCW in 2001, he never returned to the company.