Barbara Eden: How I've Kept My Jeannie Figure
05/31/2013 AT 08:00 AM EDT
Now 78-years-young, Eden assures PEOPLE that the iconic midriff-baring costume had no special alterations.
"The costume was made for a Lexus commercial I did," Eden tells PEOPLE. "About 10 years after the show went off the air. It has to have been at least 30 years."
Eden tried on the costume after she received the call asking her to attend the star-studded event, whose roster included former President Bill Clinton (with whom Eden shared the stage).
"I have a costume closet. My girlfriend said, 'Take it out, try it on and see what happens.' So I put it on and it fit!"
So how did Eden maintain her Jeannie body over the years?
"I spin three times a week," she says. "Then I work with a trainer for half an hour with weights. It's important to lift weights for your bones."
She admits her pace has changed over the years, but that it is very consistent with her workouts.
"I used to be in the front of the class," she says. "I don't do that anymore. I stay in the back, because I can't really keep up, but I do it for an hour."
And though she has a sweet tooth, she maintains a healthy diet overall: "I have a good breakfast, and I try to have protein at lunch."
It's been nearly 50 years since the first episode of I Dream of Jeannie aired in 1965 (it ran until 1970), and Eden says she's grateful for every moment since and realistic about where she is today.
"There are times when I am really upset with the time passing," she says. "But I have a loving husband [Jon Eicholtz] and really good friends. You can't possibly be what you were when you were younger. I am so lucky to be here. Really lucky."