The feud between the 26-year-old 'Transformers' star and the 55-year-old former '30 Rock' actor is reportedly heating up as Shia is holding a grudge against Alec, who he believes may have gotten him fired from the Broadway production 'Orphans'.
A source close to the young actor told gossip website RadarOnline.com: "Shia just can't let this one go, he's disgusted with Alec for getting him axed from 'Orphans'.
"He would never dream of whining to a director about a co-stars' performance, which he genuinely believes Alec did.
"Shia thinks Alec told [director Daniel Sullivan] that he wasn't up to scratch for the role and they should seek a replacement before the play's premiere.
"He says that Alec always undermined him for his lack of theatre experience, but Shia has done theatre before and isn't just a movie star, as Alec claimed.
"Now, Shia is adamant that he doesn't want to work with Alec again, and he has vowed to get even with him. He thinks he acted unprofessionally, that he's a bully and out-of-touch with reality."
Shia exited the Broadway play due to "creative differences" weeks before it was due to open, and after admitting he and his would-be co-star didn't connect as "men", he acknowledged Alec could have been instrumental in his departure from the production.
He previously said: "I'm pretty passionate and impulsive, and he's a very passionate individual as well. And I think that impulsiveness and that passion makes for, ya know, some fireworks.
"Me and Alec had tension as men. Not as artists but as men."