It was previously reported that she was in a “stable” condition.
Anne Heche is in a coma after being involved in a road collision over the weekend.
A spokesperson for the actress issued a statement following reports that she was in a “stable” condition.
The statement, which was issued to PA, said: “Previous reports stating that Anne Heche was stable were inaccurate.
“Shortly after the accident, Anne became unconscious, slipping into a coma and is in critical condition.
“She has a significant pulmonary injury requiring mechanical ventilation and burns that require surgical intervention.”
According to the LA fire department, the car crash occurred when Heche’s car struck a house, causing a fire.
An LAFD report read: “59 firefighters took 65 minutes to access, confine and fully extinguish the stubborn flames within the heavily damaged structure.
“One female adult [was] found within the vehicle, who has been taken to an area hospital by LAFD Paramedics in critical condition.”
Anne Heche is best known for her roles in Donnie Brasco, Volcano, I Know What You Did Last Summer, Six Days, Seven Nights and Return to Paradise. She is also a director.