Just how clueless is Alicia Silverstone?

The longtime animal rights activist and vocal vegan wore a silk gown by furrier J. Mendel not just once but twice.

This is the same girl who forced Anne Klein to pull a rabbit-fur jacket from their catalogue before she would even think about slipping on one of their dresses. The contrite company even offered to entirely revoke their fur licence “based upon [Silverstone’s] convictions and our belief in the same.”

When Silverstone starred in her now-cancelled TV show “Miss Match,” she even asked that costume designers create a “cruelty-free” wardrobe avoiding not just the obvious fur and leather but also silk and even wool.

But the p.r. department at J. Mendel is so good it coaxed Silverstone to slip on a silk chiffon dress and overlook the fact that it was produced in the same factory as their luxurious fur jackets and wraps. She wore it to the Los Angeles premiere of her movie “Beauty Shop,” and loved the gown so much she even wore it a second time, according to a source.

Silverstone – who was voted World’s Sexiest Vegetarian by PETA in 2004. and appeared in a PETA anti-leather ad – told CNN just last week: “I think wearing fur is unacceptable … The animals are tortured so badly. I think nobody should be wearing fur.”

“She is seen as a fashion insider and frequently writes personal letters to designers. It’s not that she doesn’t like them as designers but that she wants them to stop using fur,” said a PETA rep.

A J. Mendel rep said, “We thought Alicia looked gorgeous in the dress. It’s the best it’s ever looked on anyone.”

STEP-PUNK

Ashton Kutcher claims that he has no plans to marry girlfriend Demi Moore, though he already feels like a stepdad to the three daughters she shares with ex Bruce Willis. “Being with them on a daily basis is one of the biggest gifts I’ve ever had in my life. They kind of got the raw end of the deal. They only got one of me, and I got all of them,” he told W magazine. “That’s a good stock trade, you know.”

As for critics that slammed his performance in “Guess Who,” Kutcher is sanguine. After all, he has role models, he told the mag: “I’ll watch a Keanu Reeves movie and I’ll go, ‘Wow. He’s really not a great actor,’ But the guy works really hard and keeps doing hit movies.”

FAUX SHOW

Melania Trump had folks buzzing that she’s pregnant when she attended the Martha Graham Dance Company event Wednesday wearing an empire-waisted gown designed by Christian Dior’s John Galliano. But the Donald’s reps insist that she is not expecting, just following a trend.

INSTANT MESSAGES

* Infamous intern Monica Lewinsky almost had a run-in with political daughter Alexandra Kerry, unbeknownst to her. Both showed to pay their respects to Page Six’s Paula Froelich, who was feting her book “It!” Harvey Weinstein, Yankee Gary Sheffield, producer Elaine Goldsmith-Thomas, John Stamos, Lisa Ling, and record honcho LA Reid also came and snapped up the food prepped by celeb chefs Anthony Bourdain and Eric Ripert.

* Pamela Anderson better watch out. Her boy-toy, Stephen Dorff, was at NA snuggling with his ex-girlfriend Shannon Click. “They were holding hands the whole night and she was sitting on his lap,” said a spywitness. Alex von Furstenberg and socialite Lydia Hearst were also there last Saturday night to celebrate model Anne. V’s birthday.

* Aging sex-symbol Kevin Bacon still does it for someone, apparently. At the Wednesday premiere of his movie “Loverboy,” hosted by Gen Art, Bacon was attacked by a over-zealous fan. The Chanel-clad lady fell into his arms and proclaimed “You are so hot! I love you!” But sadly it was unrequited and she was unceremoniously dragged away by security guards.

* Billy Joel’s wife, Katie Lee, is looking for something to occupy her time: the former restaurant hostess and culinary student is launching a food Web site this fall. She showed at Gourmet editor Ruth Reichl’s book party to do some research with chefs Bobby Flay, Gray Kuntz, Marcus Samuelsson and restaurateurs Sirio Macchioni and Danny Meyer.

* Lara Flynn Boyle is hoping to kick-start her career with a new UPN drama called “Crazed.” But the teensy TV star took a break from shooting the show’s pilot to celebrate her birthday Thursday night in Los Angeles along with publicist Lara Shriftman and Molly Sims, David Spade and Kelly Lynch.

FYI: Joss Stone will get a $3,000 Asprey necklace at her birthday party at Aer after the VH-1 Save the Music concert. Not bad for 18 … Miramax lawyer Bert Fields was toasted Tuesday night by S.I. Newhouse, Dominick Dunne and wife Barbara Guggenheim for his new book “Players: The Mysterious Identity of William Shakespeare.” … Uma Thurman had two men visit her while shooting her second round of Louis Vuitton ads at the Bath House in the East Village this week: designer Marc Jacobs and son Roan.