Brett was born in Hamilton, Scotland, and studied at the London Studio Centre. She is fluent in Spanish. Brett has admitted to being a bit of a wild child in her youth, drinking heavily for 20 years. Brett speaks with a Scottish accent; however, on moving to London, she adopted a London accent – fitting for her EastEnders role. She says she has always had a "knack" with accents and has admitted that speaking with a Scottish accent becomes handy when people ask if she is Jane from EastEnders. She has admitted that when asked that question she speaks with a Scottish accent and people then assume they are mistaken.
Brett was in a relationship with a musician Dave Evans for six years. The couple met on a blind date in 2001 and got engaged; however, they split in 2007 before the wedding. Brett revealed in January 2011 that she was pregnant with her first child. She gave birth to Erin Anne Millie Brett in June 2011.
Needing an Equity Card to be a paid professional actress in the UK, she replied to an advert in The Stage and joined Circo Magico Italiano, a travelling circus, in Mexico and Central America. On her return she appeared in various productions on London's Westend Stage, including playing a prostitute in Les Misérables, appeared in the UK Tour of The Rocky Horror Show as Magenta, starring alongside Jason Donovan as Frank and appeared in the musical Smokey Joe's Cafe.
After being spotted in Les Misérables by EastEnders casting director Kat Collins. she made her first appearance in June 2004, at which time the character was known as Jane Collins. She initially signed a three-year contract, and in 2010 she signed a further one-year contract. She also appears as Jane in the 2010 spin-off series EastEnders: E20. In May 2011 Brett left the soap briefly on maternity leave. It was revealed that she would return to her role in November 2011. In January 2012 her character Jane departed from EastEnders. Brett briefly reprised her role in January 2014.
On 15 March 2012, it was announced Brett would be joining the BBC's ongoing drama Waterloo Road as Christine Mulgrew, a new English teacher hired by headmaster Michael Byrne. For the first time in Brett's career, she spoke in her native accent as the show had relocated to Scotland. Brett's character then took over as acting headteacher at the end of the eighth series and was appointed as permanent headteacher at the beginning of series 9. Brett continued to appear in Waterloo Road in the second half of series 9, despite her return to EastEnders. Brett confirmed via Twitter that she will continue filming on Waterloo Road in late Spring 2014.
|2004-2012, 2014-||EastEnders||TV||Jane Beale|
|2012-2014||Waterloo Road||TV||Christine Mulgrew|