Watch Josh Duhamel's Harvey Dent team up with Naya Rivera's Catwoman in Batman: The Long Halloween clip

The Long Halloween isn't over yet. The second and final part of the animated adaptation of the classic Batman comic by Jeph Loeb and Tim Sale hits digital this week (with a Blu-Ray release following next month). But first, you can watch an exclusive clip above featuring District Attorney Harvey Dent (Josh Duhamel) forming an unlikely alliance with Catwoman (Naya Rivera) in their shared pursuit of Gotham City crime boss Carmine Falcone (Titus Welliver).

Duhamel wasn't able to make EW's earlier video roundtable about Batman: The Long Halloween — which featured Jensen Ackles (Batman), Julie Nathanson (Gilda Dent), writer Tim Sheridan, and producer Butch Lukic — so we caught up with him ahead of the release of part 2 to discuss the psychological journey his character goes on in this story.

Anyone familiar with Batman mythos generally or The Long Halloween specifically probably knows where this is going. Though Dent starts the story as a crusading attorney determined to make Gotham safe by bringing down the Falcone crime family, by the end he ends up on the other side of the law, as the supervillain Two-Face.

"In a lot of ways it's an origin story for Harvey, the story of how he became Two-Face," Duhamel tells EW. "He really has a bipolar condition. This is a guy who's been able to keep this dual personality, this other dark menacing character, in the back of his subconscious for so long, but he's starting to crack. You start to see it in part 1 and then you really see it in part 2. It's not as if he just went from being Harvey Dent right into Two-Face; he kind of always was Two-Face."

Dent's dramatic transformation is brought on not just by a fateful faceful of acid, but also by the stresses of his investigation into Falcone — which keeps getting more and more complicated by a mysterious killer taking out important Gotham crime figures on each monthly holiday. The ever-increasing tension in his marriage to Gilda isn't helping either. Part 2 explains more about the nature of the relationship, but some mysteries might never be answered.

"There are a lot of frustrations with the investigation, and then there's also trouble at home with his wife," Duhamel says. "There was something really, really troubling about that. Probably the most interesting part of this is I cannot quite put my finger on what that relationship was about. It was like he was trying, but he couldn't get through to her because she was put off that they couldn't have kids. So he would leave the frustrations of work to go home to this cold, sterile house where he doesn't even know where he fits. All that stuff is what leads to him cracking."

As Dent transitions into Two-Face, Duhamel gets to change up his vocals — going for a more gravelly tone to simulate scarred vocal cords and a different personality taking over. This kind of change-up is precisely what Duhamel enjoys about voice acting.

"it really is fun to go in there and kind of stretch yourself and try different things," he says. "It's easy sometimes to forget how important it is to use your voice when you're acting, because it's such a visual medium. But it's as important as anything you do in front of the camera. So doing things like this is a great exercise for me in trying new things and pushing myself vocally. Not just doing things in front of a camera, but actually making a voice to get the point across, and finding different voices. It's a really fun side job, if you will."

Batman: The Long Halloween, Part Two gets a digital release July 27 and hits Blu-ray on Aug. 10.

Related content:

• Josh Duhamel on his most memorable roles: Tad Hamilton, Transformers, Jupiter's Legacy, and more
• Jensen Ackles is so glad he can finally talk about playing Batman in The Long Halloween
• See Naya Rivera hiss as Catwoman in her final role in Batman: The Long Halloween sneak peek