The Costume Institute Gala - better known as the Met Gala - is often referred to as the Oscars of fashion.
And in the style calendar there aren't many events as important as the first Monday in May.
This year is no exception as the Gala will be held on the evening of Monday, May 1. in New York.
It's a chance for A-listers to dress up in all their finery and experiment with daring trends in a way they don't normally do.
The dress code is always themed - and is dictated by that year's Costume Institute exhibition.
2017's theme is Rei Kawakubo/Comme des Garçons and the designs and dresses are expected to be even more outlandish than before.
In 2010 Katy Perry famously wore a white light-up dress, whereas Madonna and Lady Gaga regularly go for the shock factor with their choices.
Floor-length gowns are a popular choice - thanks to the grand staircase at the entrance of the museum - which allows for trains to be displayed at full impact.
Although there have been many sartorial highlights, some famous faces can get it drastically wrong - think Kim Kardashian's floral dress with matching gloves.
Take a look at our pictures below to see the worst culprits.
2015's Gala theme "China: Through the Looking Glass" became the subject of a documentary, The First Monday in May.
Tickets for the invitation-only Met Gala reportedly cost $30,000 each (£20,500) or up to $275,000 (£188,000) for a table, with the money raised going to the Metropolitan Museum's Costume Institute.
Met Gala chairwoman, US Vogue editor-in-chief Anna Wintour, has the final say over the guest list. Last year 600 people attended.