Heche was hospitalized last week after suffering a brain injury during a car crash in the Los Angeles area, per TMZ.
Her representative told TMZ that Heche was "brain dead" and under California law that is the definition of death.
A representative for the actress says life support machines are keeping Anne's heart beating but made it clear that she has no brain function, TMZ reports.
The actor, who is in a coma and in critical condition, is being kept on life support for possible organ donation, according to the statement released Thursday night on behalf of her family and friends.
Heche, who's been hospitalized at the Grossman Burn Center at West Hills hospital north of Los Angeles, suffered a “severe anoxic brain injury,” the statement said. Such an injury is caused by a sustained lack of oxygen to the brain.
“She is not expected to survive,” the statement said. “It has long been her choice to donate her organs and she is being kept on life support to determine if any are viable."
On the morning of Aug. 5, Heche’s car smashed into a house in a neighborhood in west Los Angeles and a fire erupted with the car embedded inside the home.
Earlier Thursday, police said they were investigating Heche for driving under the influence.
\ Detectives with a search warrant took a sample of her blood and found narcotics in her system, LAPD spokesperson Officer Jeff Lee said.
Toxicology tests, which can take weeks to complete, must be performed to identify the drugs more clearly and to differentiate them from any medication she may have been given for treatment at the hospital.
Evidence is still being gathered from the crash, police said, and they would present a case to prosecutors if it is warranted when the investigation is complete.
A representative for Heche declined comment on the investigation.
On Tuesday, Heche spokesperson Heather Duffy Boylston said she had been in a coma since after the accident, with burns that required surgery and lung injuries that required the use of a ventilator to breathe.
“Anne had a huge heart and touched everyone she met with her generous spirit. More than her extraordinary talent, she saw spreading kindness and joy as her life’s work — especially moving the needle for acceptance of who you love,” Thursday's statement said. “She will be remembered for her courageous honesty and dearly missed for her light.”
Heche, 53, was among the most prominent film stars in Hollywood in the late 1990s, playing opposite actors including Johnny Depp (“Donnie Brasco”) and Harrison Ford (“Six Days, Seven Nights”). In a 2001 memoir, she discussed her lifelong struggles with mental health.
She recently had recurring roles on the network TV series “Chicago P.D.” and “All Rise,” and in 2020 was a contestant on “Dancing With the Stars.”