Media playback is unsupported on your device Media caption Lady Gaga, Olivia Colman and all the Hollywood stars on the red carpet for the 2019 Oscars

The stars were out in full fashion force on the 91st Academy Awards red carpet.

Celebrities let their outfits do the talking in every colour under the rainbow.

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Here are the looks that lit up social media.

And the best dressed goes to....

Actor Billy Porter, who has won both a Tony and a Grammy for his role in Kinky Boots, stunned the red carpet in a custom tuxedo-gown.

The star of US drama TV series Pose told Vogue he's "always been inspired by fashion" and that his outfits are all about coming to terms with his gay identity.

Jada Pinkett Smith was also a big fan of the look and thanked Billy for "saving Black History Month".

Fashion fans have been raving about his Christian Siriano dress, for its perfect mix of the masculine and feminine.

It costs how much?

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Did you recognise the diamond in Lady Gaga's necklace when she stepped onto the red carpet?

The rock, known as the Tiffany Diamond, was worn by Audrey Hepburn in 1961 (in a different setting) for promotional shots for Breakfast at Tiffany's.

Jewellery giant Tiffany said it had released the gem - reported to be worth as much as $50 million (£38 million) - from its vault "specifically for Lady Gaga".

First discovered in South Africa in 1877, the 128.54-carat yellow diamond is thought to be one of the biggest in the world.

Gaga teamed the jewel with diamond earrings, elbow-length gloves and a black strapless Alexander McQueen gown with structured hips and a fishtail hem.

Selma Blair inspires at Vanity Fair's party

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Selma Blair made her first public appearance since announcing she had been diagnosed with multiple sclerosis.

She attended the Vanity Fair Oscars party in a dress, cape and walking stick.

Many people commented on her bravery and how her story could inspire others who may also have the condition.

Superman-worthy capes

Is it a bird? Is it a plane? No, it's a bunch of celebrities wearing some pretty cool caped gowns.

Glenn Close, nominated for best actress for The Wife, wore a stunning gold lamé cape dress on the red carpet.

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Melissa McCarthy, who was nominated for best actress for Can You Ever Forgive Me?, also jumped on the cape vibe in a black and white ensemble.

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Villanelle vibes

It seems that Killing Eve's favourite assassin has a few celebrity fans, judging by some of the looks on the red carpet.

Jodie Comer better look out, as she could have some rivals to contend with when season two comes around.

American actress Linda Cardellini wore fuchsia taffeta on the red carpet. She stars in Green Book and A Simple Favour.

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Crazy Rich Asians' Awkwafina served some serious looks in her glittery lilac tuxe by Dsquared 2.

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US singer Kacey Musgraves also looked pretty in baby pink - her dress is from the Giambattista Valli spring 2019 collection.

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Red carpet rainbow

While last year's awards season was dominated by sombre colours as celebrities came out to support the #MeToo and Time's Up movements, 2019's Oscars were full of every colour of the rainbow.

Dame Helen Mirren led the fashion pack in a vibrant Schiaparelli gown, complete with multi-toned pink chiffon and some seriously sparkling jewels.

Emma Stone and Rachel Weisz, who were both nominated for best supporting actress for The Favourite, fully embraced colour on the Oscars red carpet.

Emma wore a brown and gold Louis Vuitton dress, while Rachel rocked a red floral vinyl dress.

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New hair, new me?

Charlize Theron got the internet talking when she rocked the red carpet in a powder blue Dior gown and a brunette bob.

All hail Queen Melissa McCarthy

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Melissa McCarthy presented the award for best costume in perhaps the most show-stealing look yet, a Tudor frock covered in fluffy (toy) rabbits.

This paid homage to Olivia Colman's portrayal of Queen Anne's pet rabbits in The Favourite.

McCarthy's skit with Brian Tyree Henry, who looked equally fetching, set social media alight.

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