Michael Bay is in "final negotiations" to direct a fourth Transformers film, according to reports.
While details for the upcoming cyborg saga are being kept under wraps, Vulture claims the movie will not be a prequel, and that it could explore the Transformers world with the return of older characters.
"Regular people might not care about bringing out a character like Sentinel Prime. But believe me, fans of the series cared," sources told the publication.
Lead actor Shia LaBeouf has already insisted that the third film, Transformers: Dark Of The Moon, would be his last outing with the giant robots, telling MTV News: "I'm not coming back to do another one."
Producer Steven Spielberg is rumoured to be interested in another instalment, although Michael, who has directed the three previous films, has been trying to assemble a cast for the long-developing dark comedy Pain And Gain, which Mark Wahlberg and Dwayne Johnson are in talks to star in.
Production on Transformers 4 could start as early as winter 2012.