Natalie Cole has been diagnosed with Hepatitis C, her rep confirms to PEOPLE.
The Grammy-winning singer, 58, discovered she had the disease during a routine visit to the doctor, but is responding well to treatment.
"Natalie has had a terrific response to her medication and is now virus negative," Dr. Graham Woolf, Associate Clinical Professor of Medicine at U.C.L.A./Cedars-Sinai Medical Center, said in a statement."This gives her an increased chance of cure."
Still, Cole has suffered side effects from the anti-viral medicine, including fatigue, muscle aches and dehydration, but, "she is recovering from these," Woolf said.
Doctors believe that Cole's illness is likely the result of drug usage decades ago, which she documented in her 2000 autobiography, Angel On My Shoulder.
"I’ve been so fortunate to have learned so much from my past experiences," said Cole. "I am embraced by the love and support of my family and friends; I am committed to my belief in myself and in my abiding faith to meet this challenge with a heartfelt optimism and determination. This is how I intend to deal with this current challenge in my life."
Cole is expected to release her latest album, Still Unforgettable, on Sept. 9.