Ziggler aka Nick Nemeth is a fairly big deal in the wrestling world.
He debuted in WWE in the mid-2000's as "Nicky" part of a male cheerleading stable dubbed the "Spirit Squad." After they broke up he was reintroduced as "Dolph Ziggler" and was a staple midcarder on the Smackdown roster until eventually flirting with the main event. A string of concussions unfortunately kept him held back for a long period as did his habit of imitating WWE Legend Shawn Michaels' style of over-selling a bit too closely which supposedly landed him in the doghouse and ruined his chances of permanently moving into the World Title picture. However given his strong work ethic and devotion to the company he became a fixture of the midcard and this generations go-to guy of being elevation talent to the stars. Someone you knew could be trusted in making the person they're pushing to main event look good.
Outside of wrestling Ziggler has flirted with acting and has reportedly became a somewhat successful standup comedian. He once dated Amy Schumer who reportedly dumped him for being too "athletic" in bed which got him a bit of press. He's also good friends with fellow WWE Superstar Mike "The Miz" Mizanin formerly of Real World and The Challenge fame as both hail from Cleveland, Ohio. My guess is Mizanin was tied up with a movie role, his reality show, or was just taking time off to spend with his newborn daughter and suggested Dolph take his place.
To my knowledge the only thing he's previously done with MTV is this...