‘Agents of S.H.I.E.L.D.’ Season 4 Cast & Spoilers: Parminder Nagra, Jason O’Mara Join Cast; New Season To Be Darker, Sexier?

Marvel's "Agents of S.H.I.E.L.D" is ready to return for its fourth season next month, but before that, new cast members are confirmed to join the ABC drama series. "The Blacklist" star has been signed for a multi-episode arc while Jason O'Mara has been booked for a top-secret director role.

"Agents of S.H.I.E.L.D" Season 4 has added Parminder Nagra as a guest star and her first appearance can be expected in the third episode. IGN reported that Nagra will play as a power political figure, with a known distrust of Inhumans and the threat they pose to society. She will clash Coulson & Co. as they continue to advocate for their Inhuman friends. The previous season started to explore the awakening of the Inhuman gene around the world. At the end of Season 3, Daisy Johnson split from SHIELD and went out on her own.

Meanwhile, "Life on Mars" star Jason O'Mara has been cast for a role in "Agents of S.H.I.E.L.D." which remains to be a top secret until now. He is going to be the new director of SHIELD replacing Coulson (Clark Gregg), "a character whose Marvel roots go back to the 1940s." O'Mara said he honestly don't know the details, but that his character will have a big impact on the show.

"It's pretty high status. It's a little daunting," O'Mara told The Hollywood Reporter. "He's a high-status character. Suddenly he comes in and he's the boss, telling the other characters orders. Here I come in after [the other actors] been doing this for four years and I'm telling them what to do. It's a little awkward, even for me on set!"

Other cast additions include Gabriel Luna, who will play as Robbie Reyes or Ghost Rider, as the show tries to explore a supernatural aspect of the Marvel Cinematic Universe. "All the powers so far have been really rooted in something that Fitz and Simmons can always explain," Chloe Bennet told IGN. "I'm curious to see how they tie in a flaming head/skull on fire, and how they explain that with science."

As the show moves to its new 10 p.m. timeslot, Bennet teased, "You know, I read the script. It definitely felt darker. It was darker, it's a little sexier, it's edgier, it's definitely more mature this year," she shared. "Again, a new fresh breath going into the season of sexy darkness."

"Agents of S.H.I.E.L.D" Season 4 premiers on Tuesday, Sept. 20 at 10 p.m. EST on ABC.