There are few things Susan Sarandon has dared not try, and now that she has posed for PEOPLE without makeup, that list has gotten even shorter."
"I wanted to see what it would feel like," the 69-year-old says simply of her decision.
The Oscar winner, activist and mom of three is comfortable in her own skin – inside and out – and attributes her healthy natural glow to "more what I haven't done than what I've done: I don't smoke cigarettes and I don't really drink and I get bored lying around in the sun."
Sarandon says she keeps her skincare regimen pretty simple.
"I use skin oil and tinted sunblock," she says. "I'm lucky I have good skin. I definitely have lines, and underneath my eyes have definitely gotten more hollowed out, I guess, as you lose collagen."
With her usual candor, she's also open about what she has and hasn't done regarding cosmetic procedures.
"I think everybody should do whatever they want to do," she says in regards to plastic surgery. "I had something sucked out about 10 or 12 years ago [points to her eye area]. The only thing I have a problem with is when suddenly people have gigantic lips that never had gigantic lips. I'm a little nervous about anything really huge, or Botox even, because I have to use my face. But I'm all for people doing whatever makes them feel good about themselves."
Still, she adds, "It makes me uncomfortable to see really large breast and butt implants; I don't quite understand what it's like to Iive with that. It would be like sitting on your purse all the time!"
For more from Sarandon, pick up the World's Most Beautiful issue of PEOPLE, on newsstands Friday
The actress, whose new film The Meddler comes out April 22, says she believes she looked her best when she was pregnant.
"Not two days after you have a baby, you're a nightmare," she says with a laugh. "But leading up to that, you have that glow, I think because of all the extra hormones. I loved everything about being pregnant."
What Makes You Feel Most Beautiful?
As for what she's learned to love over the years, she says, "When I was growing up, everyone made fun of my eyes. They would call me 'Popeye' and all kinds of things. As I matured, I started realizing that all your imperfections are what make you what you are, and I kind of embraced that oddity, something that was specific to me.
"There is a picture of myself in grammar school, and, oh god, it's one of the saddest little things you've ever seen," she continues. "I'm skinny, with a long neck, wearing my Catholic school uniform and I have two ponytails – and my eyes, I look like a praying mantis! It's endearing, but in a very pathetic way."
Asked if a "significant other" prefers her with or without makeup, she says, "I so wish I had a significant other, but if anybody likes this spread, it will definitely be without makeup. I think that pretty much everybody I've ever been with has not gone for a heavy makeup look. I can't remember anybody's who said 'Can you go back in there and put more makeup on?' "
And if there's one situation she wouldn't be caught dead in – without makeup – she laughs and says, "Well, I just got caught dead in it. Being photographed. I just did it!"