What makes designer Christian Siriano so successful? He knows just how to flatter a woman's figure.

Decades, a vintage boutique, and actress Mena Suvari hosted a party to celebrate Siriano’s fall 2014 collection over the weekend in Beverly Hills, and the stars sang the designer's praises. "I've known Christian for years now—I love everything about him, and he always seems to know what works best on my body," Suvari (in Christian Siriano) told "I think he's very smart with his choices each season, and he really knows what's flattering on women."

Dita Von Teese recently became a fast fan of Siriano's as well. "I have a very specific look and am very particular about the pieces I like. When I saw the quality of his clothes, I thought, 'Oh, yes. This is the kind of thing I love.' All the silk linings and the way everything's finished, it's really gorgeous," she said. "When I put this dress on, it felt like it was made for me."

Siriano highly values how a design fits the body and his latest collection—which was inspired by supermodel Lisa Fonssagrives and designed in the late '50s, early '60s vintage spirit—takes on that ideal. "We wanted to do things that were luminous but still very flattering and elegant, and keep the color tones simple."

"Every girl is different, let me tell you, and I really think this collection can work for everyone." The designer predicts a glamorous turn in the upcoming seasons' styles. "I always say it's better to be overdressed than underdressed," Siriano said.

Von Teese agreed, noting that not everyone understands her desire to be done-up all the time. "When you incite love and hate at the same time, and when people call you ugly and beautiful at the same time, you're probably doing something right because you're creating strong opinions," she said.

"I want the attention of the chic and the elegant and the unusual people, not the average Joe, and I appreciate it when a designer like Christian gets my style."

--With reporting by Carita Rizzo