This report comes from the Official
Star Wars Site!
Answered by: Rick McCallum
Who
will be joining the cast for Episode III?
Look for most of the actors from Episode II to
return with the story focusing on the characters played by Hayden
Christensen (Anakin), Ewan McGregor (Obi-Wan), Natalie Portman (Padmé)
and Ian McDiarmid (Palpatine).
Basically everything's been cast except for
incidental characters. That obviously won't begin until we're
further along on the script.