With less than two months before its September 24 debut, "Agents of S.H.I.E.L.D." continues to keep the mystery surrounding its characters and plot alive, as TV Line reports "Ghost Whisperer" actor David Conrad has been cast in a recurring mystery role. Much like every mystery role in the series so far, Conrad's character is currently shrouded in secrecy, and details are unlikely to surface before Marvel is ready to reveal them.

Although the lucky few that attended the "Agents of S.H.I.E.L.D." panel at Comic-Con International 2013 had the opportunity to see the pilot well before its September air date, all other Marvel Cinematic Universe fans continue to wait patiently for the series' debut. Marvel Television and ABC have released three new TV spots featuring new footage, including an appearance by Cobie Smulders as Maria Hill. Additionally, S.H.I.E.L.D. Site has posted a number of new photos of the cast and crew during the pilot episode, including a first look at "Firefly" alum Ron Glass as one of the S.H.I.E.L.D. staffers.

Check out the clips and image gallery below.