Conversation so far:
What was the premier date?
Dreamgirls premiered on December 4, 2006 at the Ziegfeld Theatre in New York City.
Did all of the stars attend?
CANNOTANSWER.
Did anything of interest happen at the premier?
The film's Los Angeles premiere was held on December 11 at the Wilshire Theater in Beverly Hills.

Question: What was the road show?
Self-contained rewrite: What was the road show for Dreamgirls?