Conversation so far:
Was Hayden in Star Wars?
Christensen announced that he would be starring as Anakin Skywalker.
What year did this happen?
On May 12, 2000, Christensen announced that he would be starring as Anakin Skywalker in Star Wars.
Did anything happen on the set of Star Wars?
Christensen asked Lucas if a special Vader suit could be constructed.
Did they make that special suit?
Lucas agreed.
Did the fans like him as Vader?
His performance in both Episode II and III received generally mixed reviews by critics.
What else happened while he was filming Star Wars?
The casting director reviewed about 1,500 other candidates.

Question: Why did they choose Hayden?
Self-contained rewrite: Why did George Lucas choose Hayden Christensen to play Darth Vader?