Update: A report on Joni Mitchell's website refutes TMZ and Billboards' claims:

Joni is still in the hospital--but she comprehends, she's alert, and she has her full senses. A full recovery is expected. The document obtained by a certain media outlet simply gives her longtime friend Leslie Morris the authority --in the absence of 24-hour doctor care--to make care decisions for Joni once she leaves the hospital. As we all know, Joni is a strong-willed woman and is nowhere near giving up the fight.

Original Story

Joni Mitchell is in a coma and unresponsive, TMZ reports. The news follows the singer's hospitalisation last month. The news was also confirmed by Billboard, which cites "multiple sources" saying her condition is worse than what we're currently being told by her representatives.

According to the most recent update, Mitchell is at the UCLA Medical Center, where she was taken after being found unconscious at her home in Los Angeles on March 31st.