Bay: Transformers handover is tough

Michael Bay has revealed that he is directing a fourth Transformers film, because he's not quite ready to hand the series over to another director yet.

The filmmaker, who has revealed that the fourth instalment will be his final outing with the giant robots, admitted the success of the third film Dark Of The Moon made him consider another follow-up.

"I thought I was done. Then the ride came out [at Universal Studios Hollywood] and the two-and-a-half-hour lines. And then you're thinking, 'Oh my God, someone's going to take this over.' And you start doing a lot of soul-searching," he told the Huffington Post.

"The studio says they want to restart the franchise. And someone could come in here and screw it up, you know? So I'm thinking that if I do this last one, we set it on a new footing, we change a lot of things - but we keep the history of the three in place.

"But we broaden it so it can be set up and be carried on - it would have a better chance for survival, I guess. You know?"

Michael - whose next film is black comedy Pain And Gain starring Mark Wahlberg and Dwayne Johnson - added: "When you look what's going on in the film business with the franchise frenzy right now, why is [James] Cameron doing two more Avatar movies? Why is Peter Jackson doing three more Hobbit movies that are in the same world as Lord Of The Rings? When you have a franchise, it's very hard to give it up."