Moviemaker Michael Bay's fourth Transformers installment will be the first of a new blockbuster trilogy.

The new film, which stars Mark Wahlberg, is set four years after Transformers: Dark of the Night - Shia LaBeouf's last movie as Bay's leading man - and the director has revealed he has big plans for the robot franchise.

Bay says, "The story makes a very natural transition, and reason as to why we have a whole new cast. This Transformers will feel very different than the last three. We are embarking on a new trilogy."