Peter Cullen, who provided the voice of Optimus Prime in the original Transformers cartoon series told fans about his roles in an interview with The Oklahoman:
"(The filmmakers) were thinking more Hollywood big names," Cullen said. "They did start to consider the original voice actors because of the enthusiasm and the ... stubbornness of the fan base. God, I'm grateful for those guys," he said.
Cullen was called in to audition for Michael Bay at his offices in Santa Monica, Calif.
He was asked to read a scene with Optimus Prime and Ironhide, a gutsy Autobot who was a close friend of Prime's, also played by Cullen in the original series.
"The script assistant was there, and she started reading for Ironside," Cullen said.
"I said, ‘Excuse me, dear, do you mind if I read it?' Because I actually played this character.'"
Cullen completed the read-through reading for both characters.
Cullen received a callback. This time, Cullen was called to act out a more personal, one-on-one scene.
"The reason for that was, they wanted to find out if I in fact could act," he said.
"Optimus steps out of his normal frame, and becomes ... a little more human."
Shortly later, Cullen heard from his agent that he was again cast as Optimus Prime.
"And I said, ‘Oh, fantastic,' and that's when I started to get involved," he said. "It started getting exciting, and it's remained that way ever since."
Read the full interview!