According to reports from JWFan members as well as a review of last Saturday’s ‘Film Night’ concert at Tanglewood, Williams told the attending crowd that he will indeed compose the score to Star Wars: Episode VIII, and he plans to see a first cut of the film in a few weeks.
Star Wars: Episode VIII is set to be released in cinemas on December 15, 2017.
UPDATE: Williams’ speech (video and transcript):
So our producer Kathy Kennedy called me at Disney Studios a few weeks ago and said “Would you like to do the new Star Wars?” and I said “Well, yes, I think I would but the honest truth is I don’t want anybody else to write music for Daisy. So in a few weeks I will receive a first viewing of it and see who Rey’s father is, we don’t know, we’ll find out.