Duhamel told us today at the Las Vegas ShoWest convention that he met with director Michael Bay yesterday, that the script is done and they're preparing to start filming in the summer. So yes, he will indeed be back alongside Shia LaBeouf, Megan Fox and Tyrese Gibson.Thanks to Carlo for the link.
Duhamel Returning for Transformers 3
Just in case you had concerns, Josh Duhamel confirmed to SuperheroHype that he will be reprisal his role of Captain Lennox for Transformers 3 when production starts this summer. From the site: