Leonard Nimoy first lent his talents to the Transformers universe by voicing Galvatron in the 1986 animated Transformers: The Movie one-off. He will now return as the voice of Sentinel Prime, Optimus Prime's predecessor, in director Michael Bay's summer sequel Transformers: Dark of the Moon.

Sentinel Prime's wrecked body, which had crash landed on the moon and was discovered by the Apollo 11 astronauts in 1969, was first seen in the teaser trailer for Transformers: Dark of the Moon. On earth, he will take the form of a fire engine, and serve in the sequel's climactic end battle sequence that takes place in downtown Chicago.

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Michael Bay had originally wanted to get Leonard Nimoy in Transformers: Revenge of the Fallen, but was afraid that he wouldn't be able to pay the actor enough money for the voice work.

Here is what Michael Bay had to say.

"I was too scared to ask him. Plus, he's married to Susan Bay, who's a cousin of mine. So I had to be careful. I've met him at family functions. But he told me, 'I would be honored. I'm glad to be back!'"