The actor and singer revealed to Vogue why he chose wear a gown instead of a tuxedo — saying it was for a personal reason.
"I've always been inspired by fashion. My grandmother, my mom—they were always stylish. I grew up loving fashion, but there was a limit to the ways in which I could express myself," he told Vogue.
"When you're black and you're gay, one's masculinity is in question. I dealt with a lot of homophobia in relation to my clothing choices. [Even] when I had my first working contract at A&M Records, I was silent for a long time.
"Now I'm in a space where, being on Pose, I'm invited to red carpets and I have something to say through clothes. My goal is to be a walking piece of political art every time I show up. To challenge expectations."
He said his previous outfit at the Globes, where he wore a pink cape, changed everything for him.
"I had the courage to push the status quo. I believe men on the red carpet would love to play more," the star claims.
Porter said he always wanted to wear a ball gown and after watching Project Runway he knew that Siriano was perfect for the job.
After getting the Oscar's gig for hosting a red carpet pre-show, he decided to ask Siriano if he wanted to make his gown, which the designer replied with an enthusiastic yes.
"We wanted to play between the masculine and the feminine. This look was interesting because it's not drag. I'm not a drag queen, I'm a man in a dress. He came up with a tux on the top, and a ballgown that bursts out at the bottom," Porter explained.
He also said he's wearing Rick Owens shoes, as Rick is gender-blending, and Oscar Heyman fine jewellery.
"[At the first fitting in the gown,] I felt alive," the singer said.
However, he knows that some people may feel uncomfortable about his fashion choice, but said "it's not anybody's business but mine.