The actress stepped out in a minimal white Ralph Lauren Collection gown, which revealed a daring thigh-high split when she made her way down the water-print carpet.
The silk column halterneck gown, which had a 90s feel, featured a gathered panel at the hip.
She paired the stunning dress with a pair of pointed white court heels and two Jennifer Fisher bar cuffs.
Watson wore her hair swept into a chic updo, while her makeup was decidedly minimal, focusing on strong brows, youthful flushed cheeks, a pale coral lip and lots of mascara.
Watson's Noah co-star Jennifer Connelly also stunned in a very different red carpet gown - a high-necked gothic number by Alexander McQueen. The stunning design featured a shimmering floral bodice and dramatic frayed black organza voluminous skirt.
Hugh Jackman supported his Les Miserables co-star Russell Crowe on the red carpet, looking dapper in a grey suit. Noah's lead star Crowe went for a more laidback approach with an open shirt and overcoat.
Watson with her Noah co-star Russell Crowe
Director Darren Aronofsky posed with his girlfriend, Canadian producer Brandi-Ann Milbradt, on the red carpet.
English actor Douglas Booth, who plays Shem in Noah, looked smart in a three-piece grey checked suit.
