Although few details are available about Callis' character, the actor, 38, will appear in a big role in several of the season's last episodes, FlashForward showrunner Jessika Borsiczky told Sci Fi Wire.
"When I watched Battlestar, every time he wasn't in a scene I couldn't wait for him to come back," she told the site. "And I really wanted to have an opportunity to work with him. Honestly, since the show was ordered, we've been excited to work with him."
Borsiczky also hinted Callis' character will be involved with Olivia's (Sonya Walger) journey.
Are you excited to see Callis on FlashForward?