Mary Hart is in her fifties and she's hosted "Entertainment Tonight" for 27 years. So, is the affable blond TV personality looking at calling it a wrap one of these days?

She says she's given the idea of retirement plenty of thought, but don't expect her to step away from the microphone anytime soon.

"Every time we sign a new contract, I think, 'Oh, I know I'll be ready to call it quits when this is over.' But, in the last year and a half, I've realized I'm not ready to call it quits," she tells us. "I'm still having so much fun.

"I love running into Leonardo DiCaprio, George Clooney, Sandra Bullock, Governor Arnold Schwarzenegger. When you know people through the years, there's a comfort level in your interactions and that's fun. In a sense, we've matured together. And, I enjoy working with the people I see on a daily basis. There are a handful of us who've been there all the way -- Leonard [Maltin} and myself, and some of the people behind the scenes."

Although Hart confesses she sometimes misses the days when it was "all about the movie stars" in today's reality TV-packed entertainment world, there are good trade-offs in expanding the range of "ET." Giant ratings from talking to people like Jon Gosselin would be one. No doubt more satisfying for her, on a personal level: "A year ago last fall was one of the most exciting times I've ever had on the show in terms of interviews, and they weren't movie stars -- they were Michelle and Barak Obama. For me, it's really a wonderful mix of things."

She notes, "Talking to Chaz Bono about being a transgender was one of the most moving interviews I've ever done. We grew up watching Chastity on 'Sonny & Cher,' and now to hear about his journey was very affecting."

She says she approached the interview, "with a sense of empathy and curiosity, a sense of being perplexed about the whole thing. It's not easily understood how someone goes through those lengths. But, I fully believe that's the best thing for him. And it's easy for me to say him, because he's undergone such a transformation."

And she still has those celebrity encounters that make her feel like a fan. Paul McCartney quickly comes to mind.

Hart wed "ET" founding producer Burt Sugarman in 1989 and they have one son. Asked whether having a teenager around helps her stay on top of current trends in music, she answers with a laugh, "A.J. is into the classic rock 'n' roll, the classic vinyl. He realized his dad was very cool when he could say, 'Oh my gosh -- my dad had The Jackson 5 and David Bowie on his show.'"

That show was NBC's vintage weekly music fest, "The Midnight Special," which ran from 1973-1981. As Hart points out, "You name it, they were on that show."

And, she certainly has no shortage of movie stars, from Cannes through the Oscars -- which she still finds extremely exciting -- and back again.

Says Mary, "When I'm tired of it, I'll quit."