Marvel's "Agents of S.H.I.E.L.D." kicked off its second season on Tuesday night (Sept. 23) to rave reviews. A large majority of comic book fans were pleased, and according to TV by the Numbers, the show raked in an estimated 5.6 million viewers.

On Wednesday, ABC released the first official photo (via Entertainment Weekly) of Adrianne Palicki as Bobbi Morse, aka Mockingbird. Details about the character are being kept under wraps but, just like in the comics, Bobbi Morse will be the head of Hydra Security.

Eventually she goes from highly trained Shield operative to the superhero Mockingbird. According to Entertainment Weekly, Palicki will make her debut in the fifth episode on Oct. 21, titled "A Hen in the Wolf House."

She will join other "S.H.I.E.L.D." newbies Lucy Lawless as Agent Isabelle Hartly and Kyle MacLachlan as Skye's father. Palicki previously said she was hesitant to accept the role as Bobbi Morse because she feared she would never be able to play another superhero again.

"There's fear in it too. I know if I play this character, I probably would never play another Marvel character," she said. "There's different questions you have to ask, and you ask about that too. Where is this character going? All those silly fears that you get being locked into something, but I have to say working with this group of people has been amazing. These producers and show runners are fantastic and I trust them implicitly. Marvel's been really fun to work with as well, so I'm looking forward to it and I hope it's a long run for us." 

"Agents of S.H.I.E.L.D." airs Tuesday nights at 9 p.m. on ABC. Next week's second episode is titled "Heavy is the Head" and an official description reads: "Haunted and running out of solutions, Coulson puts his team right in the line of fire in the hopes of saving them all. But with General Talbot, Hydra and Creel all on the attack, can they possibly survive? Meanwhile, a mysterious Doctor harbors some dangerous secrets that could destroy one of our core team members."