She began her singing career at the age of 15 and released her first #1 hit, "Because We Want To," in 1998.
She was nominated for the Olivier Award for Best Actress for her role as Connie in The Effect in 2012.
She was married to TV show host Chris Evans from 2001 until 2007. She married her second husband, Laurence Fox, in 2007. The couple had two children before divorcing in 2016. She and singer Johnny Lloyd welcomed a daughter named Tallulah in January 2019.
She acted alongside David Tennant in numerous episodes of Dr. Who.