2Juno and Paulie Bleeker
Vivien Killilea//Getty ImagesMake like Kelly Sawyer and Jessica Alba and rock up to Halloween embodying the brilliant (and Oscar-Winning, lest we forget) film Juno. One person can go as the pregnant teen, while the other ons a curly haired wig (if you're not lucky enough to be born with those natural curls) and go as the baby's father Paulie Bleeker.
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3Gossip Girl
Arnaldo Magnani//Getty ImagesWhat better time to channel these on-screen best friends than ahead of a Gossip Girl revival? Make sure there's a headband at the ready if you're the Blair Waldorf of the pair and a loosely knotted tie for the Serena Van Der Woodsen.
4Clueless
Getty ImagesIs there anything more terrifying than two women in plaid uniforms on mobile phones with Daddy's credit card? We didn't think so. Therefore, Dionne and Cher will make an excellent Halloween costume.
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5Mario and Luigi
Cara Delevingne//InstagramIt's been done many times before - even by Kendall Jenner and Cara Delevingne - but Mario and Luigi uniforms are a great best friend option to continue to opt for, even in 2019.
6Cast Away
Nothing says 'friendship' like the love between Tom Hanks' Cast Away character Chuck and Wilson, right? Be prepared for chants of 'Wilsonnnnnn' all night long.
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7Napolean Dynamite
Be the Deb to his/her Napolean and crack out the 'Vote for Pedro' t-shirts to bring this 2004 hit film back to the forefront of people's memories, right where it belongs.
8Kate Middleton and Meghan Markle
Stephen Pond//Getty ImagesThe fact there are two Duchesses makes Kate and Meghan a brilliant and easy best friend Halloween costume. Lucky for you, we have ample outfit inspiration for both the Duchess of Cambridge and Duchess of Sussex for you.
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9Sandy and Rizzo
FOX//Getty ImagesPay homage to the 1978 high-school film Grease with your best friend. One of you can wear a cheerleader outfit/cardigan and dress/'bad Sandy' PVC while the other dons a Pink Ladies jacket, neck scarf and 'pedal pushers'.
10Romy and Michele
Relive the 90s by dressing up as the two characters from Romy and Michele's High School Reunion. Satin slip dresses, fluffy heels – quite a fun outfit in general tbh.
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11Sabrina and Salem
In an ode to the Nickelodeon teen comedy - and, the spooky revival on Netflix - one part of the duo can dress up in a joker, low-slung jeans and a blouse to channel Melissa Joan Hart's character while the other half wears cat ears, glasses and a teeny tiny waistcoat. Perfect.
12Wilma Flinstone and Betty Rubble
Slaven Vlasic//Getty ImagesAn oldy but a goodie. Also, not that difficult to do, especially if you make your own costumes! Use this picture of Today programme hosts Kathie Lee Gifford and Hoda Kotb as inspiration.
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13Dancing Emojis
An easy one which never gets old. Pair up with a friend this Halloween and don your best black leotards. Holding this position all night might hurt, but it'll be worth it.
14Eve and Gwen Stefani
L. Cohen//Getty ImagesAlexa, Play 'Let Me Blow Ya Mind'.
Cast your mind back to 2001 when this song, and video - featuring these iconic looks - were absolutely everywhere. A TBT worth reviving in our opinion.
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15The Grady twins
The Grady twins in Stanley Kubrick's hit 1980s horror film The Shining will give your friends nightmares for days, but you'll also get some pretty great compliments on the costumes. A win win situation.
16The Olsen Twins
Dimitrios Kambouris//Getty ImagesMary-Kate and Ashley's signature style is so iconic that it most definitely deserves a tribute through a best friend costume. Have a kohl eyeliner and plenty of accessories to hand.
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17Pokemon and Ash
Getty Images//Getty ImagesThough the cartoon aspect may make it seem complicated, one person needs to don some yellow ears, paint red circles on their cheeks and wear a yellow and brown animal costume. Whoever takes on Ash, needs a cap, jeans, trainers and they're pretty much done.
18'Let it go' with Disney's badass female duo, Ana and Elsa, ahead of the film's sequel release next month.

Olivia Blair is Entertainment Editor (Luxury) at Hearst UK, working across ELLE, Esquire and Harper's Bazaar. Olivia covers all things entertainment and has interviewed the likes of Margot Robbie, Emma Stone, Michaela Coel and Ryan Gosling over the years.
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