Her rep says that she is "doing much better," and receiving kidney dialysis not related to the Hepatitis C, which he adds is "under control" now.
ET also spoke to Quincy Jones recently, who had expressed his worries over her health.
"We are very concerned about her. She's not doing well right now," he said. "We had a doctor we met at a benefit the other night that says he has the new technology that could save her with Hepatitis C, so we're trying desperately to reach her to get in touch with her because she's in the hospital as we speak."
Quincy worked with Natalie's father Nat King Cole, and has known her since her childhood.
"I worked with her father in 1960, with my band in Europe and Natalie was seven years old then and she went to school with my daughter," he said. "She was a sweetie back then."