Willis, 54, the original policeman in The Village People, has been undergoing in-custody substance abuse counseling since his arrest in South San Francisco in March for drug possession and giving false identification to a police officer, he said.
At the time, Willis also faced a bench warrant for failing to appear at his October sentencing hearing on separate drug and weapons charges.
Willis has pleaded not guilty to the drug and false identification charges.
"The nightmare of drug abuse is being lifted from my life," he said in a statement Monday.
Willis said his attorney will ask a San Mateo County judge to approve his release into a residential drug rehab program at his pretrial hearing on charges stemming from his March arrest. The hearing is set for July 3.
The San Mateo County prosecutor handling the case could not be reached for comment Monday.
Willis, who co-wrote hits such as "YMCA" and "In the Navy," left The Village People in 1980. After allegedly jumping bail last fall, he was featured on a December episode of the TV crime show "America's Most Wanted."