The Disney+ sci-fi drama, in which Ewan McGregor will be returning as the Jedi sage, is currently in production, and the big casting news was revealed by Disney bosses on Thursday (December 10).
"Hayden Christensen returns as Darth Vader, joining Ewan McGregor in OBI-WAN KENOBI," an official Twitter statement reads. "The Original Series begins 10 years after the dramatic events of Revenge of the Sith, and is coming to #DisneyPlus."
"The most beautiful thing of all," McGregor wrote as the news was confirmed.
Christensen was an unknown when he was cast as Anakin Skywalker - the father of Luke and Princess Leia - in "Star Wars: Episode II - Attack of the Clones". He reprised the role in "Star Wars: Episode III - Revenge of the Sith", the film in which Anakin turned to the dark side and became one of the movie world's most feared villains.
The casting news comes a week after the death of British actor Dave Prowse, who played Darth Vader in the first three "Star Wars" movies.
Meanwhile, Disney+ bosses are also developing a "Star Wars" spin-off series based on "The Empire Strikes Back" and "Star Wars: The Last Jedi" character Lando Calrissian, created by "Dear White People" creator Justin Simien.
It's not clear who will lead the cast of Lando. Donald Glover and Billy Dee Williams have both played the character on the big screen.