Conversation so far:
What was the concept of The Wall?
In the mid-1970s, as Pink Floyd gained mainstream fame, Waters began feeling increasingly alienated from their audiences.
How was the film Pink Floyd – The Wall to be made?
The concept of the film was intended to be live footage from the album's tour, with Scarfe's animation and extra scenes.

Question: Who was to star in the film?
Self-contained rewrite: Who was to star in the film Pink Floyd – The Wall?