OUT OF THE MOUTH OF A BABE

Actress Gina Gershon shares what keeps her sexy — and why she’s ready to play a hot grandma

‘THERE are some days I feel 102 years old, and other days, like I’m 14,” says Gina Gershon, who falls somewhere in between. “I just think we’d be a much happier society if there weren’t any mirrors, and the idea of age and numbers didn’t exist!”

Gershon would rather not see her own age in print, but she’s never shied from playing women of any vintage, persuasion or size, as long as the part intrigued her — from the jaded diva of “Showgirls” to the hot-to-trot Hasidic dry cleaner of “Curb Your Enthusiasm.”

Mother roles? Bring them on — and sexy grandmother roles, too. “Not only would I play a MILF, but I’d be into playing a GILF,” Gershon tells The Post over lunch. “Look at Cloris Leachman.”

Now the woman who once played Sally Bowles on Broadway is making her Café Carlyle cabaret debut, in a show called “Wild Women Don’t Get the Blues,” which starts its two-week run on Tuesday. Backed by a four-piece band, she’ll sing and play the jaw harp, a twangy, bite-size mouth instrument that’s also known as the Jew’s harp. ("Sometimes I call it the Chosen instrument," she says.)

With her glowing skin and sleek figure, you’d suspect someone who grew up a “total tomboy” in California’s San Fernando Valley is a health nut, but she claims otherwise.

“I love junk food,” says the actress, now based in New York. “Burgers, cookies and any sort of chocolate.”

Chalk it up to her genes. She says that not only have she and her sister inherited their mother’s kewpie-doll lips, but beautiful skin runs in the family.

“[My aunt] does nothing and still looks fabulous," Gershon says. She herself relies on serums to save face. She also swears by what she calls her “retox, detox” strategy: “If you go out to a party and drink tequila, the next day you have to go to yoga class and steam and drink tons of water.”

She does flow yoga in a warm room, and hikes and swims in the ocean whenever possible. As for her beverage of choice: “I only drink silver tequila or mezcal [because] I like the way it makes me feel — and [for] its medicinal purposes.”

The “best” diet she ever did was a regimen that relied on tequila and chocolate pudding from the Odeon. Taking little bites and sips of each for a week left her 5 pounds lighter. Then again, she says, she had a parasite, “so maybe it wasn’t the diet.”

Some roles have taken a toll on her body. While making 1995’s “Showgirls,” her face swelled up: “You try putting three layers of jewels and [fake] eyelashes on your eyes and then taking them off.”

To play the lanky Corky — Jennifer Tilly’s lover in the 1996 indie thriller “Bound” — she started boxing. She says her agents urged her to forgo that role, telling her that playing a lesbian would “ruin my career.” She took it anyway, and never regretted it.

“So many women told me how this movie helped make it OK to be who they were,” says Gershon, who’s straight and shares her downtown digs with her 20-pound cat, Lord Louis Azuzu.

She was also advised not to play the singer of 2003’s “Prey for Rock & Roll” unless her 40-year-old character was rewritten as a 35-year-old. Again, Gershon held fast, arguing that age was an integral part of her character: Having 50 looming ahead made the stakes higher for her as a would-be rock star.

For now, she’s thrilled to hit the stage on her own. She recently saw 90-yearold cabaret legend Marilyn Maye’s show and was floored. She says she called her mother, who’s 86 — “but she looks 68” — to rave about it.

“I hope I’m kicking up my legs like that at 90!”