It’s the end of an era on TV as Buffy the Vampire Slayer is laid to rest. The question: How did a show that never was a big ratings winner generate thousands of Web sites, land on 12 Entertainment Weekly magazine covers, and get studied in colleges across the country? The answer: It was a smart show with a huge star, Sarah Michelle Gellar.

It’s a bittersweet ending for Sarah, who took on the role of Buffy more than six years ago and makes her final curtain call on May 20. Access Hollywood’s Pat O’Brien was on the set exclusively during Sarah’s last days of production on the series finale.

Pat O’Brien: Let’s talk about the end of Buffy because I know your heart is so into this. Was it a difficult decision to say, ’I’m moving on.’

Sarah Michelle Gellar: It was virtually impossible. You know you start a show and hope that it does well, and hope to make it past one season, and all of the sudden I realize I will be 26 and I was 18 when I started the show. I mean it’s been the largest chunk of my life that I can remember.

Pat: It is a big chunk of your life. Obviously, it’s kind of exciting to move on but then there are just too many memories.

Sarah Michelle: I don’t think the enormity of the situation has hit me. It was a very difficult decision. It’s a decision that I’ll probably second guess for a very long time, but you’ve got to take chances. I feel that we have told a lot of great stories and it was always really important to me to have the show go out on a high note.

Pat: I remember being with Calista Flockhart on her last couple of days on the Ally McBeal set. She would look around and she would see something or a person and everything had a memory. Is that starting to hit, saying goodbye to these people?

Sarah Michelle: No, I don’t think I have let that hit me. I think that if I let it hit me right now I don’t think I would be able to get through the day.

Pat: Why are you leaving?

Sarah Michelle: For a lot of reasons. Oh, goodness that’s a really big question. I’m leaving for personal reasons, I’m leaving for professional reasons and I’m a little exhausted. I have put my heart and soul into the show and I’ve always said that if I couldn’t give 110% in the show then I couldn’t do it anymore. I was an 18-year-old kid when I started and now I’m a 26-year-old married woman and there are other things in my life that need a little bit of time. That is definitely a factor. I’m leaving because the story has come to a really good place and I never want to be that show where people say, ’Is that show still on?’

Pat: Is this the end of Buffy or are you going to come back in some form?

Sarah Michelle: It’s the end of Buffy as we know it. The show Buffy the Vampire Slayer is ending. Hopefully Angel will continue. Joss [Whedon] actually asked me if I would consider doing an Angel next year and of course I had every intention of doing something for the spin-off. I initially thought that was something that I could do, and it still may be something I am going to do. But it’s just not going to be next season.

Pat: No big sweeps return?

Sarah Michelle: There is unfinished business between Buffy and Angel and we were lucky enough that The WB was kind enough to let us have David [Boreanaz] for our last two episodes here. And that is certainly something that I would like to be able to do over there also.

Pat: What do you want to say to all your fans because they have been so incredibly loyal?

Sarah Michelle: Oh God, there is so much. Most importantly I want to thank them because without the fans, this show had no chance. We were a mid-season replacement on The WB called Buffy the Vampire Slayer, based on an unsuccessful movie. People pitied me when I got this job, but I just knew there was something about this show. I’m like, ’No, guys this is different, this is going to be something, you guys are wrong about this.’ Then, all of the sudden the show became this huge success. And it wasn’t because we were in the Top 10 and it wasn’t because we were garnered with all these awards, all this praise. It was because we had die-hard fans — fans that supported our show.

Pat: So you are going to miss it?

Sarah Michelle: I am going to miss everything, but more than anything I am going to miss the people.

Pat: What can I do or say to make you completely break down here?

Sarah Michelle: Well, Barbara… (laughs)

Pat: Would you like to start a family?

Sarah Michelle: Yeah, I mean eventually that is something I want to do. I love children and I want to have more than one child. It’s not something that I am going to do tomorrow. I have learned not to say anything specific, but yes.

Pat: But that is part of your plan?

Sarah: It is definitely part of the plan and again, that’s part of moving on. There is a lot of stuff that I need to do.