TWoP: What it is that led you to appearing on Fringe?
Leonard Nimoy: I had a wonderful time working on the new Star Trek movie with J.J. Abrams, who directed it. When it was done, he asked me to look into the possibility of playing William Bell on Fringe. I was frankly not terribly aware of what it was all about. I began looking at some episodes, and saw that William Bell, the character, had been talked about rather frequently, but had never been seen. I felt that I owed JJ a favor. He did a great job on the Star Trek movie and treated me extremely well. And I'm very happy I did it. The work on Fringe has turned out to be exciting and interesting. It's a terribly well-produced series. The character was a wide-open canvas for me to work with. I had a great time doing it. This week's episode is particularly special for the William Bell character.

Your character has been a mysterious one. Is William Bell evil? Is he good?
Nimoy: The ambiguity is the drama of the character. I think all of those questions will be answered this week in the final episode. We are still not quite clear, as of last week, what his intentions are. He keeps telling Olivia that she should trust him. Maybe she has to. I don't know if she has any choice, really, but there will be very strong involvement with Olivia and with Peter and particularly with Walter, which will, I think, answer the questions that you're asking. Those are the questions that everybody's asking. So, what's it all about with William Bell? We'll find out this Thursday.

Will we see the long-awaited reunion between William and Walter in the finale?
Nimoy: Yes, there's a very strong relationship resolution between Walter and William next Thursday night. I would say that's at the heart of the episode. It was a great pleasure for me to do those scenes. I admire John. I call him, "Noble John." His name is John Noble, of course. I call him, "Noble John." He's a wonderful actor. I also am an admirer of the rest of the cast. I got to do some interesting work with Anna Torv, who I think is a wonderful actress too.

Everybody's facing off against their alternate universe doubles in these last two episodes. Will we be seeing an alternate universe William Bell?
Nimoy: We're getting close to doing a spoiler here, but I think it's safe to say there's only one William Bell that you're going to see next Thursday night. You're right. All of the others do have alternates. The alternates are fascinating. I watched last night's episode and was delighted with the way the actors have taken on different personalities for their alternate roles. I was only given one William Bell to play. That's the William Bell you'll see in closure next Thursday night.

Will we see William Bell next season at all?
Nimoy: No, I don't expect to be on next season. I have announced my retirement. I will not be doing any more television or movie acting or directing. I can tell you that I feel very fulfilled with the work that was given to me to do in this final episode. I admire all of the people on this show: Anna Torv, Josh Jackson, John Noble and all the rest. I'm excited, I'm looking forward to seeing it edited. I have not seen the edited version, but the work that we did on the soundstage and on the streets of Vancouver felt really creative and productive. I'm happy that I did it.

With your retirement, it looks like you won't be back for the next Star Trek film, but any word on maybe whether or not your good friend, William Shatner, might be in the next film?
Nimoy: I have no idea about the next film regarding Bill Shatner. I'm quite sure -- I think I can be definitive about the fact that I will not be in it. I have said that I think it's time for me to get off the stage and make some room for Zachary Quinto, who is the new Spock and a wonderful actor, looks a lot like me. And I'm very flattered that the character will be continued by an actor of that caliber. He's very well-trained and very talented. I have no expectations whatsoever even being asked to be in the next Star Trek film. I cannot speak for J.J. Abrams or Bill Shatner. If they have a common interest, I hope it works out.

Is it hard to say good-bye to acting?
Nimoy: No, it's not hard to say goodbye. I've had 60 years of working in films and television. I'm very grateful for all the great opportunities that I've had and all the people that I've met, the people I've worked with. The Fringe company, I said on my final day of shooting, was as good as any company I've ever worked with in the 60 years of my experience.

What's been the best part about your long career?
Nimoy: Well, I set out to be an actor when I was 17 or 18 years old. I left Boston, traveled to California to try to build a career. My very first efforts were very humble. I worked in a Saturday afternoon serial called, "Zombies of the Stratosphere." It was very primitive and very crude, but I was eager to do the work and happy to get it. It's been exciting to me to work on soundstages and on locations all around the world. I've worked with some great, great talents. I worked with a number of Academy Award winners and a number of Emmy winners, with wonderful, talented people. The Star Trek character, Mr. Spock, has been a blessing to me because I find it a very dignified and positive character and a great role model for a lot of people. I am one very, very grateful guy. Ever since Star Trek was put on the air in 1966, I have never even had to concern myself with whether or not I would work again. There was always work available to me. So, it's all about gratitude for me these days.

Part two of the Fringe season finale airs tonight at 9/8C on Fox. Get caught up on Fringe recaps here, watch the first part of the finale here, then check out the show's most memorable moments!