Brewster has appeared in the films Anita and Me, Mrs Henderson Presents, Hippie Hippie Shake with Sienna Miller and Cillian Murphy and How to Lose Friends & Alienate People. She has also appeared in the television series The Tudors, The Royal, Luther, and had a starring role in E4’s Nearly Famous as Kate Sherman.
Recently, Brewster played a supermodel named ‘Lydia Kane’ in the BBC series Material Girl, a British romantic comedy produced by Carnival Films that first aired on BBC One on 14 January 2010. It stars Lenora Crichlow, Dervla Kirwan and Michael Landes. Inspired by the book Fashion Babylon, Material Girl is “about a young fashion designer battling an evil ex-boss, a sexy-but-devilish business partner and snobby fashionistas to get her break in work and love.”
In 2009, Brewster starred in the horror film The Reeds, which premiered at the After Dark Horrorfest.
In 2012 she played one of the lead role in the award-winning short film Volume directed by Mahalia Belo.
In January 2013 she appeared in the BBC series Silent Witness as Deanna Collier.
On 16 November 2015, she appeared in the Canal Plus series Versailles as Marquise de Montespan. A month later she appeared as Bazine Netal, a First Order spy in Star Wars: The Force Awakens.