The Arrowverse has added an impressive list of actors to its roster, including but not limited to John Barrowman (Torchwood), Victor Garber (Alias, Titanic) and Wentworth Miller (Prison Break). Even though The Flash managed to snag fan-favorite Katee Sackhoff for a villainous role, the show's biggest casting shocker came at Comic-Con International in San Diego, where it was announced that Danny Trejo would play Breacher, the father of Jessica Camacho's Gyspy. According to executive producer Andrew Kreisberg, the idea of Trejo's casting started as a joke before they decided to reach out to the actor.

"Gypsy and Jessica [Camacho], they’re so tough and so strong. We’re like, 'Obviously she came from somebody strong,' and we just thought it would be a hilarious idea for Cisco, who’s managed to melt Gypsy’s heart, being unable to do the same with her father," Kriesberg told Entertainment Weekly. "We were in the room and we were like, 'Who could we get?' and someone said Danny Trejo and we all started laughing like, 'He’d be great, but of course Danny Trejo’s not going to do this.'"

RELATED: Flash Season 4 Will Take Earth-2’s Wells on ‘Epic Emotional Journey'

"But as I’ve discovered over these past few years, if you don’t ask, you don’t get it," he explained. "So we reached out to him and his people, and it turned out he was a fan, and he was eager to do it, and he loved the character. I feel like we wrote him a great script. His character and his storyline with Cisco and Gypsy, it’s part of this slight redirection of the series this year -- it’s just doing much more fun stories and much more just out and out hilarious things to match Barry’s newfound optimism and lightness."

Starring Grant Gustin as the Scarlet Speedster, The Flash returns Tuesday, October 10 at 8 p.m. ET/PT on The CW. The series also stars Jesse L. Martin, Tom Cavanagh, Carlos Valdes, Candice Patton, Danielle Panabaker, Keiynan Lonsdale and more.