Jon Favreau will voice a ''cool and important alien'' in 'Solo: A Star Wars Story'.

The 51-year-old star shared a photo of himself alongside the movie's director, Ron Howard, and its writer Lawrence Kasdan on Twitter earlier this month, and now the 63-year-old filmmaker has revealed why Jon had taken a break from directing the upcoming 'Lion King' movie to join them on set.

He retweeted Jon's post - which was simply captioned ''#starwars #solo'' - and wrote: ''Wondering why we r all together? @Jon_Favreau is voicing a very cool & important alien character for #HanSolo Flattered & fortunate I could pull him away from his #LionKing directing duties (sic)''.

However, Ron ruled out a similar role for himself.

Asked by a fan if he'd voice a character, he replied: ''Nope :-). Zero chance. But thanks for asking (sic)''

The 'Swingers' actor is a big 'Star Wars' fan and previously voiced Pre Vizsla in several series of animated spin-off 'Star Wars: The Clone Wars'.

And at one point, the 'Iron Man' filmmaker was one of many names in the frame to direct 'Star Wars: The Force Awakens' and admitted at the time he felt ''giddy'' just to be considered for the project.

He said: ''I have had the good fortune of working with George [Lucas] and around George, and whether it is doing a voice on 'Clone Wars', or being at the Skywalker Ranch mixing 'Iron Man' - so I have been very happy and lucky to just experience the culture that Lucas has created, both in my own life growing up as a kid and professional - whether it was interviewing him at film festivals on stage, he is just a really wonderful, talented gifted guy who has changed the business so much, so I am just giddy, first and foremost as a fan, to see what happens with it.

''I think there is a lot of question marks of how they are going to do it, and who they are going to do it with, and what the story is going to be about; but to say that I am not excited about it is definitely an understatement. We'll see.''