She is up for Best Performance by an Actress in a Leading Role at the 98th Academy Awards on Sunday.
But has already taken home best-dressed, stunning in an elegant black strapless gown by Dior on the red carpet at the Dolby Theatre in Hollywood as she arrived with her husband .
The Bridesmaids star, 46, exuded timeless glamour in the dramatic floor-length mermaid gown, which featured intricate floral embroidery.
The dress was adorned with delicate white floral motifs across the bodice, which cascaded down into the skirt that flared out into a trumpet-style silhouette and sweeping train.
While the couture gown made a strong statement on its own, Byrne elevated the look with a striking, oversized diamond choker that sparkled under the bright red carpet lights.
She paired the dazzling necklace with statement gold earrings.
Rose Byrne took home best dressed at the 98th Academy Awards, stunning in an elegant black strapless gown by Dior on the red carpet at the Dolby Theatre in Hollywood
Rose was supported by her husband Bobby Cannavale
The Bridesmaids star, 46, exuded timeless glamour in the dramatic floor-length mermaid gown, which featured intricate floral embroidery
The Sydney-born star made sure her dress and jewels were centre stage by sweeping her brunette locks into a sleek updo.
For her makeup she opted for a bold red lip and luminous, glowing skin.
The mermaid-style dress hugged Byrne's figure before flaring out at the hem, creating a striking silhouette as she confidently walked the red carpet.
It is a big night for Byrne who has scored her first-ever nomination.
Off the back of her win, she is nominated for Best Performance by an Actress in a Leading Role for If I Had Legs I'd Kick You.
Speaking about her major nod, Byrne said she was in complete shock.
'I can't believe it. I feel like I've snuck into the back of the bus,' she told The Hollywood Reporter in January.
'The thought of the legacy and the pageantry and the scale of it, it's impossible to not have that value.
The dress was adorned with delicate white floral motifs across the bodice, which cascaded down into the skirt that flared out into a trumpet-style silhouette and sweeping train
While the couture gown made a strong statement on its own, Byrne elevated the look with a striking oversized diamond choker that sparkled under the bright red carpet lights
The Sydney-born star made sure her dress and jewels were centre stage by sweeping her brunette locks into a sleek updo
For her makeup she opted for a bold red lip and luminous, glowing skin
The mermaid-style dress hugged Byrne's figure before flaring out at the hem, creating a striking silhouette as she walked the carpet outside the Dolby Theatre
She beat both Emma and Kate for the Golden Globes trophy earlier this month, winning Best Performance by a Female Actor in a Motion Picture – Musical or Comedy.
Viewers will see a familiar face as Conan O'Brien will return to host after he helped last year's ceremony .
The 98th Oscars
