'Once Upon a Time in Hollywood' premiere: All the glam red carpet arrivals

"Once Upon a Time in Hollywood," indeed!

Co-stars Leonardo DiCaprio, Brad Pitt and Margot Robbie led the flood of celebrity arrivals Monday night at the premiere of Quentin Tarantino's new film, with DiCaprio sporting a buttoned blue suit and Pitt opting to ditch the typical necktie. Robbie's angelic ivory gown marked one of her best style moments to date.

Pierce Brosnan brought an unexpected +1: His 22-year-old son Dylan, whose light-wash jeans and shoulder-length hair made for an appropriately boho-chic look. ("Once Upon a Time" is set in 1969.) Standing several inches above his dad — who's 6'1!" — it's no surprise that Dylan is an up-and-coming model.

Coupled up on the carpet were Britney Spears and beau Sam Asghari, John Stamos and wife Caitlin, and Sofia Vergara with husband Joe Manganiello. Meanwhile, Demi Moore and Bruce Willis' three daughters, Scout, Tallulah, and Rumer, wore silky numbers in coordinating colors. The glam sisters are looking more alike than ever these days.

After the premiere, the stars and more than 1,000 guests (!) toasted with Casamigos tequila and sipped Icelandic Glacial spring water at a party at the Roosevelt Hotel. See all the best snaps from the big night in the gallery above.

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