Feb. 7 (UPI) -- Christian Siriano doesn't understand why many fashion designers only dress one body type.
The 34-year-old fashion designer discussed his commitment to size inclusivity during Thursday's episode of Watch What Happens Live.
Siriano has famously provided looks for Leslie Jones, Bebe Rexha and other celebrities who said other designers refused to dress them. He said it's "very weird" that more designers don't create fashion-forward clothing for all sizes.
"I talk about this all the time, because it's not that hard," Siriano said. "I think people get in their own way."
"I can't imagine, because if I didn't have clothes in a lot of sizes I would have never dressed Oprah [Winfrey], I would have never dressed Beyoncé, I would have never dressed Meghan [Trainor]," he added. "You have to have options. I think it's very strange if you don't."
Siriano told Time magazine in 2016 that he supports women of "all ages and sizes" after dressing Jones for the Los Angeles premiere of Ghostbusters.
Siriano has created memorable red carpet looks for a diverse group of people. On WWHL, he commented on the tuxedo ballgown Billy Porter wore to the 2019 Oscars, saying the look helped Porter with his "red carpet renaissance."
"I definitely think we helped," Siriano said. "We took all the risks this first night and then that led to him being comfortable with whatever he wants to wear."
Siriano serves as a mentor on the Bravo series Project Runway, which premiered its 18th season in December.