According to Cedars-Sinai Medical Center spokeswoman Sally Stewart, Murphy died at 10:04 am local time on Sunday (20Dec09). Stewart would not provide a cause of death, or any further information.
The Los Angeles Fire Department responded to a call at 8 am from a home that is believed to belong to Murphy's husband, British screenwriter Simon Monjack.
Online reports suggest Murphy died after suffering a cardiac arrest at the Los Angeles home she shared with Monjack, where paramedics arrived after the actress' mother allegedly discovered her unconscious in the shower.
According to TMZ.com, Murphy could not be revived by paramedics and was pronounced dead on arrival at the hospital.
The actress' publicist Nicole Perna confirms the tragedy, but has not elaborated on the circumstances surrounding Murphy's death, telling WENN, "In this time of sadness, the family thanks you for your love and support. It is their wish that you respect their privacy."
Murphy's acting career began in the 1990s with small television, commercial and film roles. Her big break came when she landed a leading role in teen hit Clueless alongside Alicia Silverstone in 1995.
She is also well known for starring in Eminem's 8 Mile and comic-book adaptation Sin City.
The late star provided the voices for several animated characters, including Luanne Platter on more than 200 episodes of U.S. TV series King of the Hill and Gloria the penguin in 2006 film Happy Feet. That same year (06), she released the single Faster Kill Pussycat, which became a dance club hit.
Murphy recently wrapped her scenes in Sylvester Stallone's upcoming film, The Expendables, set for release next year (10).
She dated Ashton Kutcher and appeared as on-screen lovers with the hunk in 2003 comedy Just Married. The pair split the same year (03). She was later briefly engaged to production assistant Joe Macaluso in 2005, before marrying Monjack in a Jewish ceremony in 2007.
The Los Angeles Coroner’s office has launched an investigation into the cause of her death, reports RadarOnline.com.