The family of Anne Heche say the American actress "will be deeply missed but lives on through her beautiful sons" following a car crash in Los Angeles last week.
Under California law, Heche, 53, is legally dead but her family say they are keeping her heart beating and she has not been taken off life support as they seek a match for organ donation, in respect of her wishes.
Heche suffered significant burns and lung damage after crashing into a two-storey house in the Mar Vista area on the morning of Friday 5 August.
Preliminary blood tests showed "signs of narcotics" in her system and her family said she was "not expected to survive" after the collision left her in a coma.
The Los Angeles Police Department (LAPD) has said additional testing is required to rule out any substances that were administered in hospital.
In a statement her family said they had "lost a bright light, a kind and most joyful soul, a loving mother, and a loyal friend".
"Anne will be deeply missed but she lives on through her beautiful sons, her iconic body of work, and her passionate advocacy," they added.
"Her bravery for always standing in her truth, spreading her message of love and acceptance, will continue to have a lasting impact."
Ellen DeGeneres, Heche's former partner, said: "This is a sad day. I'm sending Anne's children, family and friends all of my love."
While Nancy Davis, a friend of the actress, wrote on Instagram that "heaven has a new angel".
"My loving, kind, fun, endearing and beautiful friend Anne Heche went to heaven. I will miss her terribly and cherish all the beautiful memories we have shared," she said.
On Thursday Heche's family issued a statement saying: "Unfortunately, due to her accident, Anne Heche suffered a severe anoxic brain injury and remains in a coma, in critical condition. She is not expected to survive.
"It has long been her choice to donate her organs and she is being kept on life support to determine if any are viable."