How Chris Hemsworth's Transformers One Voice Compares To Classic Optimus Prime

Spoilers for "Transformers One" to follow.

Peter Cullen is Optimus Prime, the best cartoon hero performance next to Kevin Conroy as Batman. But while Cullen's many performances as the Autobot leader make him inseparable from the character, he's not the only one who's played the part. Some Prime voice actors, like Jon Bailey and Jake Fushee, do Cullen impressions. Others offer more distinctive takes, like Garry Chalk as Optimus Primal in "Beast Wars" or David Kaye in "Transformers: Animated." Now, there's a new member of this pantheon: Chris Hemsworth, who voices a young Optimus Prime (then known as "Orion Pax") in the new animated film "Transformers One."

Reactions to the casting in "Transformers One" was mixed. Using celebrity performers instead of seasoned voice actors? Ugh. Does Hemsworth shake off the skepticism and fill these big shoes? He can obviously play a superhero; he's been acting as Thor for 13+ years now. But are such strait-laced roles where he thrives the most? 

Earlier this year, Hemsworth played 2024's best silver screen heavy: biker gang warlord Dementus in "Furiosa." A totally different character from Optimus, but also a leader who inspires with charisma. "You just want to die for the guy," said the Autobot Crosshairs (John DiMaggio) about Optimus once, the same way Dementus gets his troops' blood flowing into battle. (He doesn't do it with brilliant strategy, that's for sure.) Can Hemsworth still leave such an impression in a role that doesn't let him go hog-wild the way "Furiosa" did?

Peter Cullen's Optimus Prime voice has changed over the years. In the original "The Transformers" cartoon he was a man (er, bot) of action with a John Wayne drawl. He'd even trash talk. ("You're old, Megatron! Yesterday's model, ready for the scrapheap!")

As Cullen has aged, his Optimus voice has deepened and his performances reflect that. He plays the part more solemnly, delivering every line with earth-shaking gravitas. His more recent "Transformers" performances, in the live-action films and 2010 cartoon "Transformers: Prime," reflect how "Transformers" isn't just a job for him anymore. Cullen has been playing Optimus, on and off, for 40 years; the character is an inseparable part of his life. He also based his voice as Optimus on his brother, the late Larry Cullen, who advised him that a hero like Optimus should "be strong enough to be gentle."

Is Hemsworth's involvement with "Transformers One" all about securing a movie star to headline the cast? Probably, yeah. But remember, the film is a prequel. For most of the movie, Hemsworth is playing Orion, not Optimus. Cullen's current Optimus voice radiates gravitas and wisdom; it wouldn't fit for a younger character who doesn't have those qualities (yet). As long-time "Transformers" producer Lorenzo Di Bonaventura explained to Variety, "We couldn't use Peter because the audience needs to feel the character's youth." Indeed, "War Dawn," the original "Transformers" cartoon episode that revealed Optimus' backstory, featured Orion voiced by the more youthful sounding Laurie Faso, not Cullen.

As for Hemsworth's performance on its own merits? It's as solid as Cybertronian steel. Hemsworth is a natural comedian and the film plays into that skillset, depicting Orion as a hothead who never lets an ill-advised idea or plan get away from him. The film's core journey is seeing how this hot shot becomes Optimus Prime, and Hemsworth rises to the occasion as his lines get more serious. Take how Hemsworth first delivers Optimus' catchphrase, "Transform and roll out," with the right balance of confidence and uncertainty. As he rallies his fellow miners into the Autobots, he speaks with conviction born of empathy.

Orion only truly becomes Optimus Prime in the final minutes of the film; when he does, Hemsworth's voice drops in pitch. Now, he has said he wasn't going for a Peter Cullen impression with his performance. Nevertheless, in the film's closing moments, especially the customary "I am Optimus Prime" speech, he starts to speak with Cullen's grave cadence. No-one will mistake it for an exact impression, but it still channels the spirit of Optimus Prime.

Then there's the film's other lead; D-16, or the future Decepticon leader Megatron (played by Brian Tyree Henry). Unlike Cullen as Optimus, Megatron doesn't have a singular voice actor who everyone agrees is the definite one. This makes the villain more flexible for reinterpretation than his heroic counterpart.

Frank Welker first played Megatron in "The Transformers" by employing a screechy voice of arrogance and bluster. Like Cullen, Welker's Megatron voice has changed over the years — even more so, becoming much deeper and scarier.

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David Kaye (the only actor who's played both Optimus Prime and Megatron as a regular role) voiced "Beast Wars" Megatron like he was reading Shakespeare. Corey Burton in "Transformers: Animated," meanwhile, voiced the Decepticon leader with a voice as deep and cold as a frozen cavern. Then, in some previous stunt casting, Hugo Weaving was brought in to voice Megatron in the first three live-action "Transformers" movies. Weaving can do a good villain in his sleep, but he's admitted Megatron was just a paycheck gig; it's a competent performance, but an indistinctive one.

How does Brian Tyree Henry compare? For the first half, his voice seems very unlike Megatron, and that's the point! D-16 sounds very normal and evenly-pitched, a chill dude if a bit of a worrywart, because when the story begins that's all he is. But as D-16 grows angrier, Henry's performance grows more and more intense.

The reborn Megatron captivates crowds with righteous anger, but it's not only the loud moments when Henry excels. His delivery when Megatron chooses to let Orion die, swearing "I'm done saving you"? Chilling.

Each major Megatron voice actor most excels at one quality of the character. Welker is sinister, Kaye is grandiose, and Burton is calculating. Henry, meanwhile, nails Megatron's fury. He doesn't sound like a smirking villain or a cold mastermind; he's a young revolutionary driven to right injustices, unaware he's driving off the deep end. His Megatron voice feels like it could almost come out of a heroic character's mouth — underlining how D-16 didn't have to go down such a dark path.

The short of it? If "Transformers One" winds up being a new beginning for more animated movies, fans should have every confidence in Hemsworth and Henry as this franchise's new anchors.

"Transformers One" is now playing in theaters.