Born in Fleet, Hampshire, Aubrey attended King's College London from 1984, where she studied Classics and Archaeology. While there, however, her love of acting grew, and during a year studying in Italy where she joined a traveling theatre company, Aubrey decided to apply for drama school on her return. She did, and went on to train for three years at the Central School of Speech and Drama.

In 2001, Aubrey married production designer Steve Ritchie, whom she met several years earlier while filming in Newcastle upon Tyne. They have two daughters, Blythe and Lola-Blue. She is the cousin of David Howell Evans (The Edge), Guitarist of the U2.

Aubrey was born and brought up in Fleet, Hampshire, the daughter of Dr. Roland and Sylvia Aubrey. She is half Welsh and half English. She had two siblings. Her elder sister Sian who died in 2011, and her older brother Jonathan.

Aubrey's subsequent films include Winterbottom's Welcome to Sarajevo, Stephen Poliakoff's Food of Love — for which she won Best Actress at La Baule European Film Festival — Faenza's Lost Lover, Giacomo Campiotti's Time to Love, Richard Eyre's Iris, Fernando Meirelles's Constant Gardener and Brian Gibson's Still Crazy, nominated for two Golden Globes. Other features include Matt Lipsey's Caught in the Act, and Mat Cod's Super Eruption. Television work includes The Village; The White Queen, Criminal Justice, Vera, Hunted, and the highly acclaimed Five Daughters. Her recent feature films are Scott Hicks's Fallen; Mitch Davis's Stuck; Fabio Guaglione's Mine; and Brad Furman's Infiltrator. Juliet is currently playing Lily Hill in a new TV series for Sony called "SNATCH".