KEY POINTS:
Marilyn Monroe's sexy white halterneck outfit has been voted the most iconic movie dress of all time.
The frock, which famously flew up as Marilyn stood on a subway vent in The Seven Year Itch, beat the little black dress worn by Audrey Hepburn in Breakfast at Tiffany's.
Saucy cartoon star Jessica Rabbit's sexy, tight-fitting red dress in Who Framed Roger Rabbit took third place.
The spotty dress worn by Julia Roberts in Pretty Woman came fourth, followed by Sharon Stone's white sleeveless outfit in Basic Instinct.
There were a couple of surprises in the top 20, with Robin Williams' shapeless dress in Mrs Doubtfire coming 10th and Guy Pearce's outlandish frock in The Adventures of Priscilla, Queen of the Desert landing 18th position.
Other famous dresses to make the poll, conducted by online fashion shop missbutterfly.co.uk, included Snow White's yellow and blue frock and Julie Andrews' coat dress in Mary Poppins.
A spokesman said: "Marilyn Monroe's white halterneck dress is truly iconic and is instantly recognisable worldwide.
"It goes to show what a powerful medium film is for fashion and actresses are often defined by what they wear from Audrey Hepburn's little black dress to Julie Andrews coat dress as Mary Poppins.
"However, I'm not sure people will be flocking to copy Mrs Doubtfire's shapeless dress or at the other end of the scale - Guy Pearce's outrageous cross-dressing numbers!"
Missbutterfly's top 20 iconic movie dresses:
1. Marilyn Monroe in her white halterneck dress - The Seven Year Itch
2. Audrey Hepburn's little black dress - Breakfast At Tiffany's
3. Jessica Rabbit's strapless red dress - Who Framed Roger Rabbit
4. Julia Roberts' spotty polo dress - Pretty Woman
5. Sharon Stone's white sleeveless dress - Basic Instinct
6. Carrie Fisher's long white dress as Princess Leia - Star Wars
7. Olivia Newton-John in her white prom dress as Sandy - Grease
8. Judy Garland's gingham dress as Dorothy - The Wizard of Oz
9. Snow White's blue and yellow dress - Snow White and The Seven Dwarfs
10. Robin Williams in his blousy dress - Mrs Doubtfire
11. Vivian Leigh's red off the shoulder dress playing Scarlett O'Hara - Gone With The Wind
12. Audrey Hepburn's black and white race day dress - My Fair Lady
13. Julie Andrews' smock dress - The Sound of Music
14. Doris Day in a yellow dress - Calamity Jane
15. Julia Roberts' long red dress - Pretty Woman
16. Cruella de Ville's black dress with polka dot coat - 101 Dalmatians
17. Jennifer Grey's pale pink dress worn for the final dance as Baby - Dirty Dancing
18. Guy Pearce's outlandish frock - The Adventures of Priscilla, Queen of the Desert
19. Julie Andrews' coat dress - Mary Poppins
20. Belle's yellow ball dress - Beauty and The Beast