From the yellow gown to the Belle bun, the actress had clearly taken inspiration from the Disney princess when it came to putting together her Oscars look.
Alicia's gown, with a full, mullet-style hemline and delicate embellishment, was custom-made from Louis Vuitton.
She paired the creation with silver two-strap barely-there sandals and dazzling drop diamond earrings.
Speaking to E! host Ryan Seacrest on the red carpet ahead of the event, Alicia said she loved the colour of her dress because it "spices it up a bit".
Alicia took home her first ever Oscar at the ceremony, being crowned the Best Supporting Actress.
The 27-year-old beat favourite Kate Winslet, as well as fellow nominees Rooney Mara, Rachel McAdams and Jennifer Jason Leigh to scoop the coveted prize.
As soon as her name was announced, a shocked Alicia turned to her boyfriend Michael Fassbender who was seated next to her and gave him a discreet kiss. The Swedish beauty then hugged her mum before taking to the stage.
Alicia, who was being recognised for her role in The Danish Girl, looked visibly moved as she accepted her accolade.
The actress thanked her parents, saying she "wouldn't have believed them" if they had told her she would win. "To my mum and dad, thank you for giving me the belief anything can happen," she said.
Alicia also paid a special mention to her co-star Eddie Redmayne, as well as the film's director Tom Hooper, who she struggled to find in the audience.