'Bill & Ted 3' will feature multiple versions of the film's titular characters.

Alex Winter - the actor and filmmaker who played Bill S Preston alongside Keanu Reeves as Ted Theodore Logan in the earlier films - explained the third movie will start with Bill and Ted in their 40s.

He told Yahoo! Movies UK: ''It fits very neatly in the [series]. It's not going to feel like a reboot.

''The conceit is really funny: what if you're middle-aged, haven't really grown up and you're supposed to have saved the world and maybe, just maybe, you kinda haven't?''

The 49-year-old actor explained that by including multiple versions of the main characters in the new film, the audience gains an insight into what they've been doing between the second and third movies.

He added: ''[It's] answering the question: 'What happened to these guys?'

''They're supposed to have done all this stuff, they weren't the brightest bulbs on the tree, what happened 20 years later? To answer that question in a comedic way felt rich with possibility.''

He said, too, that the original screenwriters Chris Matheson and Ed Solomon, as well as Keanu Reeves and himself have been the guiding influences behind the sequel.