Blair Underwood is a 30-year Hollywood veteran, dating back to his role in the hip-hop film "Krush Groove" and subsequent breakout role on "L.A. Law." On TV and in film, he's played in multiple genres -- but the superhero realm was something new to him until his stint on "Marvel's Agents of S.H.I.E.L.D." earlier this year.

On the ABC series, he plays Dr. Andrew Garner, a psychologist and the ex-husband of S.H.I.E.L.D. agent Melinda May (Ming-Na Wen, who went to college with Underwood). He's set to return to "Agents of S.H.I.E.L.D." starting with next week's episode, "Purpose in the Machine," as the series deals even more directly with the growing population of superpowered Inhumans.

CBR News spoke with Underwood last week at a screening of the third season premiere of "Agents of S.H.I.E.L.D.," about how his character fits into the show going forward, acting in the superhero genre for the first time and grounding his performance in a "Marvel-ous" world.

CBR News: Blair, you've worked in many different genres in your career, but a show like "Agents of S.H.I.E.L.D." is something new for you. How different has this experience been for you?

Blair Underwood: I've never done anything like this. That's why I jumped at it. First of all, this is one of my oldest and dearest friends from college, back in the day [points to Ming-Na Wen on the red carpet, who also attended the Carnegie Mellon School of Drama] -- I heard she was doing it, I'd get to work with her. I was like, "I'm in. Count me in."

How much fun has it been playing in this world?

It's been amazing. I brought my 14-year-old son here today. We've got a 14, 16 and 18-year-old -- 90 percent of what I've done, they've never seen. The fact that I've started doing the show, they were like, "Oh, this is cool! You're in the Marvel Universe!" I'm having a ball. It's all new stuff. This is my 30th year in this business, and to your point, I've never done anything like this.

Were you a fan of this type of material? Maybe hoping to get the chance to work on something like this?

Absolutely hoping to do it. And never saw it coming.

It's been established that your character is coming back for season 3 -- what can you say about how Dr. Andrew Garner figures into things when we see him again?

As you know, this season's really about building this Inhumans team -- these "Secret Warriors." Being built primarily by Coulson and Daisy, but my lane in that is as a psychologist. He does the evaluation of all the Inhumans; as when we met him, he was evaluating Skye, helping her make that transition. It's a lot of transitional stuff. But it's all new. You got all these special powers, everybody's different, everybody's power's different -- he's trying to figure it out, and he's a little off-balance himself.

Right, you're an outsider to it.

The character and the actor!

What's that been like to play as an actor, being thrown into the deep end of a crazy superpowered world?

I just felt, as an audience member, when I watched this show, or superhero/science-fiction -- when it works best is when the characters believe it. As an actor, I just believe it. Whatever's going on, no matter how fantastic or "Marvel-ous" it seems, you root it. You ground it, and you believe it.

The third season premiere of "Marvel's Agents of S.H.I.E.L.D." airs 9 p.m. Tuesday, Sept. 29 on ABC.