If you're going to give a voice to Optimus Prime's predecessor Sentinel Prime, then that voice just can't have gravitas.  It must have geek gravitas.  EW reports that Leonard Nimoy will provide the voice for Sentinel Prime, whose wrecked body is seen in the teaser trailer for Transformers: Dark of the Moon. Nimoy previously provided the voice of Galvatron in the 1986 animated film The Transformers: The Movie.

EW also has details on Sentinel Prime's role in the film.  Hit the jump for those details.  Transformers: Dark of the Moon stars Shia LaBeouf, Rosie Huntington-Whiteley, Josh Duhamel, John Malkovich, Tyrese Gibson, Frances McDormand, and Ken Jeong.  The film opens in 3D on July 1st.

[Warning: Spoilers ahead]

According to EW, Sentinel Prime is brought to Earth, and he takes the disguise form of a fire engine in the movie’s massive, climactic battle through Chicago. I hope that instead of actually fighting in the final battle, Sentinel Prime just goes around trying to put out all of the fires caused by the fighting between the other transformers.