Billy Porter arrives at the Oscars on Sunday at the Dolby Theatre in Los Angeles. Picture: Richard Shotwell/Invision/AP

Hollywood - Hollywood's biggest stars strutted their stuff on the Oscars red carpet Sunday, and a few trends emerged: old school glamour, metallic gowns, lots of pink, trousers on the women... and one stunning gown on a man.

Actor-singer Billy Porter wowed the crowd with a Christian Siriano black velvet tuxedo gown. 

"When you come to the Oscars, you must dress up," the Tony and Grammy award-winner and star of the TV series Pose tweeted.

When you come to the Oscars, you must dress up. Thanks @CSiriano for creating this custom couture masterpiece. @OscarHeymanBros you have outdone yourselves with your iconic jewels. Style by @sammyratelle Grooming by Anna Bernabe. @TheAcademy #AcademyAwards2019 #oscars #oscars2019

— Billy Porter (@theebillyporter) February 24, 2019

While Billy Porter trended on Twitter, the designer also tweeted: 

Shutting the carpet down In a Siriano velvet tuxedo gown! #billyporter at the #oscars @theebillyporter

— Christian Siriano (@CSiriano) February 24, 2019

Porter also stunned at the Golden Globes last month in his bejeweled gray suit and hot pink cape.