Many thanks to Becky Read for posting the link!
Becky Reed attended the Q&A session with Justin Szlasa at the British Film Institute in December. She has written a piece with information gleaned from the Q&A session for the UK release of Side by Side today.
Mr. Szlasa talks about what Keanu brought to the table, the nightmare of scheduling interviews with the star and equally famous directors, the fact that Keanu pitched in and hauled lights around and many other aspects of the project.
You can read the piece here.