From frat house to femme fatale.

Sharon Stone says she’s rediscovering her feminine side now that her three sons have grown up and flown the nest.

The “Basic Instinct” bombshell revealed on Wednesday’s episode of “Late Night with Seth Meyers” that she’s back in “lady underwear” after 25 years of wearing boxer shorts and living in what she called a “stinky fraternity house.”

“You do not wear lady panties when you have so many boys,” Stone said. “You’re just a dude.”

With all three now living on their own, the actress, 67, has reclaimed her closet, her bathroom — and, apparently, her underwear drawer.

“This is a bit of a debutante ball for you,” Meyers quipped.

“I’m back out,” Stone agreed. “I’m a girl again. I feel really feminine again. I grew my hair back — it’s amazing.”

Stone w

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