From answers.com plus other websites: He took on the role of a younger Obi-Wan Kenobi in the Star Wars prequel trilogy, a role originally made famous by Sir Alec Guinness in the original Star Wars films. McGregor took very special care (especially in Star Wars Episode III: Revenge of the Sith) in his portrayal of Kenobi to ensure that Obi-Wan's mannerisms, speech timings, and accents closely resemble Obi-Wan's "Alec Guinness Self". In appearing in Star Wars films, he was continuing a family tradition of sorts: his uncle, Denis Lawson, had played Wedge Antilles in the original Star Wars trilogy. McGregor, though, has stated that the Star Wars films were the worst work that he has done and that he regrets being in the films. He later clarified that his apparent dislike of working on the Star Wars films were due to the fact that most of the scenes were shot using green rooms and background for CGI, instead of with actors and live sets. McGregor was also offered the role as James Bond in Casino Royale but turned it down. He did not comment why. So yeah, I think Ewan does have some of Alec Guinness in him, a lot of sources point to his displeasure. I still love the guy and love his acting in Star Wars, but I kinda doubt he'll be back at this point.