ShutterstockThere are a few voices that just can’t be separated from their characters. Hulk’s screams will always be Lou Ferrigno, C-3PO will always be Anthony Daniels, and Optimus Prime will always be Peter Cullen. The longtime voice actor was behind a number of recognizable characters, including King Kong, the Predator, and Eeyore, but for many fans, he will always be Optimus Prime. Cullen recently passed away at the age of 85, so let’s take a look back at one of his most affecting performances of the robot in disguise — one that shows how crucial his character was to the franchise as a whole. On August 8, 1986, The Transformers: The Movie hit theaters. It was supposed to refresh the cast and make room for new characters — and therefore new toys — but fans were unprepared for what they were about to walk into. It began like any other Transformers adventure, with the Autobots fighting the Decepticons, but about a half hour into the runtime, Optimus Prime is fatally wounded. Just like that, the leader of the Autobots and arguably the protagonist of the show itself perished. Even though he technically won his fight with Megatron, he was still too wounded to recover. Transformers: The Movie shocked fans by showing Optimus Prime dying. | Deg/Hasbro/Marvel/Kobal/ShutterstockThat loss looms large over the rest of the movie, as the Autobots try to cope with grief and defeat the planet-eating Unicron, famously played by Orson Welles. By the end, Hot Rod reluctantly takes on the helm as leader, but Optimus Prime was always the true leader of the group in cultural memory. In fact, his character was brought back in a two-part episode just a few months later in February 1987. This is a testament to Cullen’s performance — even with a robotic character, his voice was so key to the heart of the series that he had to return not long after, a choice that was fueled by fan demand. He ended up playing Optimus for over 40 years, including in Michael Bay’s live-action Transformers movies well into the 21st Century. In 2021, Transformers producer Lorenzo di Bonaventura made it clear the role was his as long as he wanted it. Peter Cullen remained the go-to voice actor for Optimus Prime for decades after the original series. | Jim Ruymen/UPI/Shutterstock“Peter Cullen brought this character to life with his amazing voice back in 1984. Is he returning? Absolutely,” he said at a press event. “There’s, there’s no discussion without him, really, you know, unless he didn’t want it. That would be the only way he would not be in here.” Unfortunately, Cullen’s passing makes this return impossible, and other actors have since taken on the role, including Chris Hemsworth in 2024’s Transformers One. But it’s Cullen’s Optimus Prime that fans grieved in 1986 and are now grieving again forty years later. But as Optimus Prime said all those years ago: “Do not grieve...soon, I shall be One with the Matrix.” The Transformers: The Movie is back in theaters for a short time: starting September 17 through September 21, 2026.