Phil Lord and Christopher Miller were fired from 'Solo: A Star Wars Story' because their ''process'' didn't suit LucasFilm.

The directorial duo signed up to the project - which focuses on the origins of the Rebel Alliance leader, played by Alden Ehrenreich - in July 2015 and began shooting last February, but they stepped away from the movie in June and were replaced by Ron Howard and now LucasFilm President Kathleen Kennedy has explained why they were let go.

She told Entertainment Weekly: ''I think these guys are hilarious, but they come from a background of animation and sketch comedy.

''And when you are making these movies, you can do that and there's plenty of room for improvisation, we do that all the time, but it has to be inside of a highly structured process or you can't get the work done.

''And you can't move the armies of people to anticipate and have things ready. So, it literally came down to process. Just getting it done.''

But the 64-year-old executive insisted it wasn't an easy decision to make.

She added: ''I just say over and over again that, yes, it was an incredibly difficult decision that we had to make and obviously it was pretty late in the game, which shows we spent a lot of time trying not to have to make that decision. And I think both Chris and Phil are enormously talented and incredibly funny..

''When all of this came together, all of us wanted nothing more than to have this be an incredible working experience.

''And when it was not working out as we had all hoped, it wasn't out of lack of talent.''

''Solo: A Star Wars Story'', now directed by Ron Howard, blasts into theatres on May 25.