Inside Christian Siriano’s ‘Amazing’ and Intimate 40th Birthday Bash in N.Y.C. (Exclusive)

Happy birthday, Christian Siriano!

The fashion designer, 40, reined in the new season of life with his closest friends — many of whom he has designed for — on Nov. 18.

To kick the evening off, Siriano celebrated at a candle-lit dinner alongside Drew Barrymore, his “muse” Alicia Silverstone, Saturday Night Live alum Leslie Jones, Real Housewives‘ Bronwyn Newport, as well as Patrica Clarkson, Debra Messing and more. The party continued a short walk away at The Mulberry, a subterranean speakeasy-style bar in Manhattan’s Nolita neighborhood.

Former Wicked star Shoshana Bean even sang for the birthday boy, as did “Unwritten” singer Natasha Bedingfield.

Celebrating in classic New York fashion, the party was glamorous, brimming with creative talent and oversize champagne bottles.

Project Runway‘s winner-turned-mentor was perfectly at home, waltzing behind the bar throughout the night to chat with the bartenders, who were serving up signature dirty martinis and spicy margaritas.

He’s an investor at the celebrity hotspot and hosted a Met Gala afterparty there in 2024, which, per PAPER, was perhaps the only one to continue after 4 a.m.

If there’s one takeaway from the night, it’s that Siriano knows how to have a good time.

Siriano, who recently dressed Kelsea Ballerini at the 2025 CMAs, says the festivities were “amazing.”

“It’s the best,” Siriano tells PEOPLE. “And it’s fun when it’s like Shoshana [Bean], and Alicia Silverstone, and Ashley Longshore, who are your friends because you get to hang out.”

Bean, who he has designed for, also gushed about her pal.

“He sees things that the world tells us are not beautiful or acceptable,” the former Broadway Elphaba says. “He sees the beauty in things that the world tells us are not traditionally beautiful, and that is the magic of his generosity.”

The youngest winner of Project Runway, Siriano has spent years building his career, clientele and friendships. An atmosphere of mutual admiration was evident at the birthday bash.

Last year, while promoting his book All Walks of Life, Siriano told PEOPLE that his kinship with celebrities enhances his work.

“I think the clothes are the best when you know the person a little bit more,” he said. “That’s a lot of the reason why a lot of people that are in my book chose to wear me, it’s a more personal thing.”

One of his closest friends, Clueless actress Silverstone, collaborates with Siriano frequently and danced with him all night long in a stunning black lace dress.

“Me and Alicia Silverstone, I think we fight over every outfit,” he jokes. “But then she always trusts me, and it always looks good.”

Another client and friend is Real Housewives of Salt Lake City‘s Newport, Siriano shared on Andy Cohen’s Watch What Happens Live! last October.

“Bronwyn is like my No. 1 customer and has been shopping, everyone, for years and spends real money,” he said at the time. “We make her literally couture, all of her confessionals are Siriano pieces that she bought years ago,” he spilled.

Reflecting on big 4-0, Siriano tells PEOPLE he’s not exactly sure what the milestone means to him, but he knows he’s come a long way.

“I started my career when I was 20 years old, and it just feels great,” he says. “It feels so fun. We had a beautiful night tonight.”