US actor Anne Heche has died aged 53, after suffering a serious brain injury in a car crash in Los Angeles last week, according to media reports

The fiery crash left Heche comatose with a "severe anoxic brain injury," media outlets quoted a representative on Thursday.

Heche has been comatose since crashing her car into a two-story house in the Mar Vista neighborhood on August 5, resulting in  "structural compromise and... heavy fire" at the scene, according to the Los Angeles Fire Department.

The ensuing blaze took 59 firefighters 65 minutes to contain and fully extinguish, the department said.

Local media reported that preliminary tests had come back positive for narcotics, though more were needed to ensure the drugs had not been administered in the course of her treatment.

Celebrity gossip outlet TMZ, citing unnamed police sources, said Heche had tested positive for cocaine and fentanyl, with the latter sometimes used for pain relief in clinical settings.

Heche starred in a number of movies from the 1990s including Six Days, Seven Nights, Donnie Brasco and I Know What You Did Last Summer.

Heche is also known for her role in the soap opera "Another World," for which she won a Daytime Emmy in 1991. 

During the 1990s, she was in a high-profile relationship with talk show host Ellen DeGeneres.