The action star has taken on a comedy role in the new movie where he plays a grown man reunited with a life-size version of his treasured childhood teddy bear, Ted, who quickly starts to come between him and his girlfriend (Mila Kunis) and Seth was impressed with Mark's range.
He told Empire magazine: ''There's not much he can't do. He's extraordinarily versatile. It's always surprising because he's such a humble guy who's not showy about it.
''He'll just very quietly come onto the set and do anything you throw at him and do it brilliantly. Mark's character has to pull the audience into this reality in a way that makes it seem like not that big a deal. He has to be able to talk to an empty space with the comfort that would show he was talking to another live actor and Mark just knocked that out of the park.''
Seth admits the movie ''asks a lot'' of Mark but says he was more than capable.
He added: ''There's broad physical comedy in the movie, there's subtle dialogue comedy. It asks a lot of an actor. And Mark had displayed so many different skills in so many different movies that he seemed like he would be the perfect balance. He could give us everything we needed, every style.''