"I don't think America knows what a gay parent looks like: I am the gay parent ," the entertainer tells ABC News' Diane Sawyer in her first in-depth interview about her sexuality.
There's no earth-shattering coming-out story, O'Donnell says, just a realization that dawned on her in a private moment. "When all my friends in high school, my girlfriends, were going out to bars and picking up men and fooling around on the beach," she says, "I would get Diet Coke and I was the designated driver. So it was never like a priority for me. I never thought about it."
When she was 18, she thought about it. "I remember driving my car when I got my permit," she says. "I was alone and I was like, 'I totally think I'm gay.' Like I says it out loud in the car."
She first fell in love with a woman a couple of years later; but she also had male lovers.
"It took me a while to understand and to figure out all that things that made me me, where I was most comfortable, who I was, and how I was going to define my life," she says. "And I found the coat that fit me."
Her sexuality never has been and is not now a big deal for her, she says. "Part of the reason why I've never said that I was gay until now was because I didn't want that adjective assigned to my name for all of eternity. You know, gay Rosie O'Donnell."
O'Donnell, who lost her mother when she was 10 and describes her father as not very available, says being gay was not that big of an obstacle in her generally difficult childhood.