It's a cameo that "Mayans M.C." fans can't stop talking about, and one that was apparently in the works for years. "CM Punk on Mayans! YO WHAT THE HOLY F**K?!" wrote Twitter user @BWDBlackWrestl1 after seeing Punk show up in Episode 4. "CM Punk in Mayans was the surprise I needed," tweeted another fan named @Jam_Pacman13. "Heels now Mayans my dude is working hard," added @MarioMedDiaz, in reference to Punk's other big TV role on the Starz wrestling show "Heels."

According to showrunner Elgin James, Punk's appearance in "Mayans M.C." ultimately stemmed from a meeting that they had several years ago. "We're both on the straight edge world," James told Gamespot in a recent interview. "We met a few years ago and I was just like, 'Yo, I gotta do something with this dude.'" That something turned out to be a small, recurring role in Season 4 of "Mayans M.C." as an Army veteran named Paul, who is friends with Vincent "Rocco" Vargas' character Gilly. Rocco reportedly used his actual experiences as a real-life Army vet to help guide Punk through his performance. "Rocco talked to him for about an hour,'" James said to Gamespot. "Of course... [Punk] just brought it, not only physically but also emotionally," he added.

People who watched the fourth episode of "Mayans" couldn't agree more. "I've seen him act a bit in Heels but man....he impressed the hell out of me last night," tweeted @valenicole. "I want more of him on here. He was so good."