Kevin Costner, 46, reopened an old chestnut this week when he repeated his story about fashioning a sequel to his 1992 hit “The Bodyguard” for Princess Diana. In the original film, Costner played a bodyguard who falls in love with his client, a rock star (Whitney Houston). “I had talked with Princess Di a couple of times,” Costner told British talk show host Michael Parkinson in an interview to be aired on Saturday. “I explained to her that I was going to try to make this movie for her, and she was genuinely interested.” The actor, who has told this story before (cynics questions the veracity of the tale the first time), said the princess had not committed to doing the project but was “genuinely excited” by the prospect. Costner said that he received the final draft of the script on the day Diana was killed in a Paris car crash in August 1997. “I was devastated by it. She was a very graceful woman and it is a great loss to all of us,” Costner, who is in London to promote his movie “Thirteen Days,” told Parkinson.