The 25-year-old singer opted for a sheer Gucci top with ruffle and lace detailing paired with high-waisted pants.
Styles completed his look with a drop earring, several flashy rings — which included a nod to his initials "H" and "S" — as well as teal and black nail polish.
The One Directioner, who is co-hosting the event in New York City, arrived with Gucci creative director, Alessandro Michele, who is also co-chairing the evening.
This year's gala theme, "Camp: Notes on Fashion," was inspired by a seminal 1964 essay by Susan Sontag in which she describes the phenomenon as something that shan't be talked about: "To talk about Camp is therefore to betray it."
The theme is the basis for the Costume Institute's spring exhibition.
The Associated Press contributed to this report.