Unlike our one-hour dash to the high street, costume designers on film sets have weeks, even months, to cogitate and trial the perfect dress for a party scene.
Short or long? Red or black? Accessories or no accessories? They have the answers perfected.
This might be the reason why some costumes never leave our collective memory, no matter how many years have passed.
They've become a benchmark for the most beautiful dresses and while exact matches are often never attainable, the high street can come remarkably close...
Keira Knightley’s green gown in Atonement
Back in 2007, we walked out of the cinema after watching Atonement with one thing on our minds: THAT GREEN DRESS. It was long, slinky, bold and elegant all at once, in a perfect shade of emerald-meets-shamrock green.
It went on to be named the best film costume of all time and has proudly held the title since. For years we've searched far and wide for a dress that replicated Keira Knightley's costume, but few have come close. That is until now...
Julia Roberts’ black lace cocktail dress in Pretty Woman
If you google 'Pretty Woman dress', photos of Vivian dressed in a floor-sweeping, off-the-shoulder red gown will flood your page. But in our opinion the most memorable outfit is this lacy black cocktail dress, which she wears to dinner after the hotel manager helps her find an outfit on Rodeo Drive. It's the ultimate transformation.
Buy it: Paper Dolls lace pencil dress with fluted sleeve, £68, asos.com
Audrey Hepburn’s little black dress in Breakfast at Tiffanys
No black dress says timeless elegance quite like Audrey Hepburn's gown in the opening scene of Breakfast at Tiffany’s. It's been copied time and time again and is the ultimate inspiration for simple black party wear.
Buy it: Halter neck dress, £12.99, zara.com
Alicia Silverstone’s red slip dress in Clueless
A variety of slip dresses dominated Cher's 60-outfit-strong wardrobe. From this vintage red number to the iconic white Calvin Klein dress, Cher inspired a trend for spaghetti straps that dominated the late nineties – from the wardrobes of Rachel and Monica in Friends to Laney Boggs' makeover moment in She's All That. And it's still big news today, with a legion of celebrity fans keeping it current.
Buy it: Rouleau slip dress, £29, topshop.com
Images: Rex Features