New York City ? So you thought they were gone — gone forever — until Kate Middleton hit the scene.

Then Marc Jacobs put them on the runway, Banana Republic partnered with “Mad Men” and, suddenly, everywhere you look, sheer hosiery seems to be in fashion again.

Since the heyday of the ’80s, there’s been a casual revolution, a revolt against power suits and the sexy secretary skirt. Both lent themselves to covered-but-sheer legs.

Now, why do women need pantyhose? They wear pants, get spray tans and slap on the Spanx. Because legs look better when you wear them, says Cathy Volker, executive vice president of global licensing for Donna Karan, including Donna Karan Hosiery.

“It’s like mineral cosmetics on your skin but better,” says Volker, who promises the pantyhose of today boasts many advances since previous versions. The fabric is more comfortable, the elastic less restricting and they can offer toning and shaping benefits, she says.

Celebrity stylist Sophia Banks-Coloma is sold. She wore sheer pantyhose to a recent red carpet event in Los Angeles. “I do think they are coming back. I especially love them in black or white with a seam up the back. We’re not talking ‘Mrs. Doubtfire’ tan stockings, but nice, flattering pantyhose and tights.”

Erase any image of brownish, loose legwear that pools at the ankles, she says, and start imagining the stylish Duchess of Cambridge or her sister, Pippa. No one is mistaking them as stodgy or uncool, Banks-Coloma says.

Noni Cavaliere, a social-media marketing specialist in New York, wears them; her favorites are those with the sexy Cuban heel and back seam. Pantyhose flatter and help a woman appear professional and feminine, she says.

“You have that ‘Mad Men’ influence everywhere, and the very feminine office look is popular again,” says the 30-year-old Cavaliere. “I’ve worked on Wall Street where women wear suits and heels, and I’ve worked in the tech world where people wear ripped jeans, flip-flops and a ripped T-shirt. I couldn’t do that. I like looking like a girl all the time, and pantyhose is part of that.”

Pantyhose should be a given for job interviews, says Julie Perez, a 22-year-old apparel studies student at the University of Arkansas. “My professors say, ‘Hosiery — you still have to do it. Yes, it’s 2011, but you have to do it.'”

Market research firm NPD puts women’s hosiery sales in the U.S. at more than $3 billion, up 2.9 percent from May 2010 to May 2011.