The Met Gala, an annual benefit event for the Costume Institute at the Metropolitan Museum of Art in New York, is considered one of the world's biggest fashion events.
It is known for its exclusive guest list, its expensive tickets and - most of all - its extravagant outfits, based on a different theme each year.
This year, that theme was Camp: Notes on Fashion - to coincide with an upcoming exhibition at the Met, inspired by US writer and political activist Susan Sontag's 1964 essay, Notes on Camp.
The outfits this year will, therefore, like the exhibition, be based on "irony, humour, parody, pastiche, artifice, theatricality and exaggeration".
And showing everyone how it was done at the very start of the night was singer Lady Gaga, who arrived in a billowing pink outfit which was not quite what it seemed at first glance.
Check out the 'Campest' red carpet looks below: