Joss Whedon is well known for turning to certain actors again and again for television and movie projects: Alexis Denisof, Amy Acker, Nathan Fillion, Eliza Dushku, Tom Lenk. Now add "Angel" alum J. August Richards to that list.

TVLine reports the actor, who played vampire-fighting gang leader turned legal mastermind Charles Gunn on the "Buffy the Vampire Slayer" spinoff, has been cast in an unknown but "super top-secret" role on Whedon's "S.H.I.E.L.D." TV series.

ABC declined to comment, leaving fans to speculate wildly about which character Richards might portray, with a young Nick Fury (in flashback) being the most obvious guess, although Marvel's Nick Fury Jr. isn't outside of the realm of possibility. Of course we can't discount that it could be a new creation (in which case, why the secrecy?).

Richards, who co-starred on TNT's "Raising the Bar," recently made a guest appearance on the canceled CW drama "Emily Owens, M.D." On "S.H.I.E.L.D.," he joins Clark Gregg as fan-favorite Agent Coulson, Ming-Na as Agent Melina May, Elizabeth Henstridge as Agent Gemma Simmons, Iain De Caestecker as Agent Leo Fitz, Brett Dalton as Agent Grant Ward and Chloe Bennett as Skye.

The pilot, which wrapped production in early February, is being fast-tracked for a spot on ABC's fall schedule.