James Gunn has finished the first draft of 'Guardians of the Galaxy 3'.

James Gunn

James Gunn

Following the successful release of the first two Marvel Cinematic Universe movies the screenwriter-and-director has been busy working on the next instalment and the initial story is now complete.

Speaking at E3, he said: "I'm writing 'Guardians of the Galaxy Vol. 3' and I finished the first draft of the treatment yesterday which I'm excited about and I feel really great about it."

Gunn has teased that he is planning on making a change to his own continuity because he has come up with a plot idea that requires it, he just hopes he doesn't upset fans.

He added: "I did something in the first movie of 'Guardians' where it was in the background but it was distinctly there and people know that it's there. And I'm like goddammit because I have a really good storytelling reason for breaking the canon and I stayed up the other night figuring out if I'm gonna do it or not. I still don't know.

"In the first movie there is a the mugshot sequence where the characters go through and they're going through the mugshots and having their picture taken and the Nova Corps has information about each of the characters coming up on their little machinery.

"Now, those things are something that your average viewer doesn't see at all and doesn't read but there's a lot of background I put into those things about who they've worked with, where they're from, what's going on. And it's one of those things that I'm thinking about changing."

The 'Guardians of the Galaxy' series stars Chris Pratt as Star-Lord, Zoe Saldana as Gamora, Dave Bautista as Drax, Bradley Cooper as Rocket and Vin Diesel as the fan favourite Groot.

The Guardians will be joining the rest of the Avengers in the upcoming 'Avengers: Infinity War' and 'Avengers 4' as they go head-to-head against intergalactic supervillain Thanos.