Michael K. Williams has signed up to star in the Han Solo 'Star Wars' spin-off movie.

The 'Boardwalk Empire' actor is the latest name to join the cast of the highly-anticipated movie, which explores the origins of the Rebel Alliance leader, but as with all previous casting announcements, details of who the 50-year-old star will be playing and their significance to the plot, are being kept under wraps.

News of his casting was announced by Variety.

While the movie - which stars Alden Ehrenreich in the lead role - is shrouded in secrecy, J.J. Abrams recently teased it has an ''amazing script''.

The 50-year-old filmmaker - who was at the helm of 'Star Wars: The Force Awakens' - said: ''I can tell you it is an amazing script and the cast is obviously extraordinary. I think it is a thrill to be a part of something that meant so much to me as a kid and to be part of allowing it to mean so much for kids now.

''It is fun to see it live on in various forms and ways even five years ago I would have never imagined it would have continued and knowing what is coming up is even more exciting.''

Fans were recently given a first look into the new movie when bosses released the first picture of the cast together to coincide with principal photography officially starting at Pinewood Studios in London last month.

Directors Phil Lord and Christopher Miller said: ''Watching such inspired people from all over the world, with such unique voices, come together for the sole purpose of making art, is nothing short of miraculous. We can't think of anything funny to say, because we just feel really moved, and really lucky.''

A few of the plot were also revealed, with the story set to follow Han Solo and his sidekick Chewbacca as they encounter Lando Calrissian (Donald Glover) ahead of the events of 'Star Wars: A New Hope'.

The as-yet untitled Han Solo spin-off movie is slated for release in 2018.