Chris Hemsworth returns to San Diego Comic-Con alongside Brian Tyree Henry and Keegan Michael Key to reveal the new trailer for their animated prequel Transformers One

Chris Hemsworth made his long-awaited return to San Diego Comic-Con on Thursday to debut the new trailer for his animated film Transformers One.

The 40-year-old actor was a longtime fixture in Hall H at the San Diego Convention Center when he played Thor in the Marvel Cinematic Universe films.

Now he’s back for Transformers One, Paramount’s animated prequel to the Transformers franchise, in theaters September 20.

He was joined by co-stars Brian Tyree Henry (D-16), Keegan-Michael Key (B-127) and director Josh Cooley during the panel in Hall H, where the trailer was shown to fans for the first time.

The film tells the origin story of two of the most iconic characters from the Transformers franchise: Optimus Prime (Hemsworth) and Megatron (Henry), back when they went by other names: Orion Pax and D-16.

Hemsworth took the stage in Hall H of the San Diego Convention Center wearing a white T-shirt under a white short-sleeved shirt and a long gold chain.

The actor also wore a silver watch and light blue jeans as he greeted Comic-Con fans once again.

He, along with his fellow actors and the director, discussed the film and unveiled the latest trailer, which shows how Optimus Prime – then known as Orion Pax – and Megatron – then D-16 – used to be best friends.

The trailer opens with Hemsworth’s voiceover saying, “For thousands of years, we’ve been at war,” as Optimus and Megatron are shown battling it out.

“But before we were enemies… we were like brothers,” Orion says, as they flash back to many, many years ago, when Orion and D-16 were best friends.

They both had jobs in a factory, but in one of the scenes it is shown that not all of these robots could transform.

Some of the larger transformer robots bump into D-16 as he tells them to watch where they step.

One of the larger bots says, “It’s not like you can transform,” as Orion fires back, “Hey Darkwing. My finger can transform. Guess which one,” mocking the iconic Transformer sound as the angry bot tries to hit him… but D-16 blocks the punch.

“Leave me alone,” says D-16 as he punches Orion himself, later thanking him for his support, with D-16 saying, “Whatever happens.”

Orion, D-16, Elita-1 (Scarlett Johansson), and B-127, also known as Bumblebee (Key), are all depicted watching an “SOS message from Earth’s surface.” They investigate, ostensibly to prove to the Transformers that they have more to offer.

“It’s time to show you that we’re more than what meets the eye,” says Orion, as the four robots approach what B-127 jokes is “a cave with teeth.” “There’s nothing scary about that.”

They go exploring and encounter an ancient Transformer known as Alpha Trion (Laurence Fishburne).

“I see power in you. Take these and use them to your full potential,” Alpha Trion tells them, effectively turning them all into Transformers.

They show the robots struggling with their transformation abilities, while Orion eventually transforms into the iconic red truck. Alpha Trion says, “How you use this power is ultimately up to you.”

Orion says softly, “We’re rolling out,” but none of the others can hear him as Elita says, “Louder,” and he says, even louder, “Transform and roll out!”

Orion tells D-16 that he wants to “help build a better world,” but D-16 insists, “We can be so much more.”

Elita tells Orion that she has noticed that D-16 is “different” because she has seen him point his huge weapon at someone.

“Yes, yes, no, I noticed that,” says Orion, and B-127 insists, “I noticed that too.”

The trailer shows the Autobot and Decepticon logos being spoofed. Orion says, “We could have built the future together,” but D-16 says, “I don’t think so.”

The trailer ends with Orion saying, “Now is the time for us to stand together, as one,” while the final shot shows Decepticons Starscream and Soundwave and Shockwave as B-127 says, “Guys, raise your hand if your name has wave in it? There’s a lot of waves.”