Invincible’s creator got emotional over working with Peter Cullen, the voice of Optimus Prime

The first trailer for season 2 of Amazon’s animated series Invincible came with a grabby surprise for fans: a splash page of the many actors who will join the voice cast, including the Sonic movies’ Ben Schwartz, I Think You Should Leave star Tim Robinson, Back to the Future’s Lea Thompson, Orphan Black’s Tatiana Maslany, Black Panther’s Sterling K. Brown, Avatar: The Way of Water’s Cliff Curtis, voice-over industry vets Phil LaMarr, Paul F. Tompkins, and Rob Delaney, and many more. For longtime animation fans, though, one name particularly stood out: Peter Cullen, an animation legend best known as the voice of Autobot leader Optimus Prime in Transformers media going back to 1984.

For Robert Kirkman, creator of the Invincible comics (and the Walking Dead comics, among many others), getting Cullen on the series was an emotional moment that reaches back to a primal childhood fandom. As a screenwriter and producer on the animated adaptation, he got to work directly with Cullen, which he describes as a challenge. When I spoke to Kirkman via Zoom about what to expect in season 2 (more of that to come), a prominent poster for 1986’s The Transformers: The Movie was visible on the wall just behind him.

“Working with Peter Cullen was a huge test for my professionalism,” Kirkman says. “Just flat-out, every fiber of my being was screaming, Don’t ask him about Optimus Prime. Don’t talk about Optimus Prime. What are you doing? Just be a professional, come on.

Image: De Laurentiis Entertainment Group

Kirkman says that “thankfully,” the voice sessions for seasons 2 and 3 were recorded via Zoom. He and series writer-producer Simon Racioppa could sit in to observe, but they kept their cameras off and stayed quiet “to keep everything focused” between the director and actor.

That didn’t entirely keep Kirkman and Racioppa from interacting with their voice talent. “If we had some kind of specific note — or, you know, if I wanted to crack a joke with Jason Mantzoukas [who plays Invincible series regular Rex Splode] — we could pop in and be annoying,” Kirkman says. “But for the most part, we would be on a text thread while the voice director was working with the actor, after introductions and things like that.

“And that was a godsend, because — you know, to say there were tears is embarrassing, but whatever, I’ll say it. Optimus Prime, big part of my life, you know? I’ve been hearing Peter Cullen’s voice since I was like 7 years old. So to have him voicing the character he voices — it’s crazy to have written dialogue that’s coming out of his mouth. It’s really something else.”

Amazon hasn’t yet released a rundown of what roles the new cast members will be playing in Invincible seasons 2 and 3, which were recorded back to back. But from that first trailer, fans spotted that Cullen will voice Thaedus, leader of the Coalition of Planets, a key player in the war against the show’s superpowered conquering species, the Viltrumites. (Don’t follow that link unless you want spoilers; we know a lot about Thaedus from Kirkman’s Invincible comics, which the Amazon series follows fairly loyally. But it isn’t yet clear how much of his background might be a secret, or how it might surface throughout season 2.)

Image: Prime Video via YouTube

Kirkman says he never wrote an Invincible character with Cullen or any other actor in mind — and that he’s grateful he doesn’t hear any particular voices in his head when he’s writing. “That’s a real blessing for me,” he says. “When I’m writing the comics, I guess I’m hearing my voice, or just some kind of amorphous voice. Maybe I’d be a better writer if I was casting voices and writing to the voices. It was fun on Walking Dead, because I was still writing the comic when the show happened, so I would start hearing the actors’ voices when I was writing a comic. Andrew Lincoln is Rick Grimes, so when I was writing Rick Grimes, I would hear Andrew Lincoln’s voice.

“But with Invincible, that comic was over and done with by the time we got to the show. Writing the early scripts, I knew I wanted to cast Steven Yeun, but I hadn’t yet heard him as Invincible. There were times, especially writing season 2 and season 3, where I was like, Oh, I think we could get this person, that’d be totally great! And I’d consider that, but I still don’t hear their voice when I’m writing.”

Kirkman says that not fan-casting actors for his characters makes it easier to be open-minded about a casting director’s suggestions on a show: “Because you’re not coming in with an expectation. When the casting director and other people suggest people, you can go, OK, yeah, I can hear that! You’re not fighting against some benchmark you’ve set in your head that you have to somehow achieve. It’s a much more open process.”

The first half of Invincible’s split season 2 will launch on Nov. 3, with the second half of the season coming in 2024. Polygon will have more from this interview with Kirkman as we get closer to the new season’s release.