'Transformers 4' is set to be released in the summer of 2014.

Producer Lorenzo di Bonaventura has confirmed Michael Bay - who helmed the first three films in the series - is going to direct the movie.

He told MTV News: "Yeah Michael's gonna direct and it'll be releasing in the summer of 2014.

"We're excited and I think the challenge there is we really are gonna do a reboot, and what that's gonna be we don't even know yet."

Lorenzo revealed there will be a "whole new story" for the forthcoming motion picture and "a lot" of new characters, but no one from the previous three films have signed up yet.

He added: "It's a hybrid because there's still continuity going on, and there will be a lot of new cast.

"Whether there's anybody from the first cast, we don't even know yet. But it's going to be a whole new story."