Britney Spears voluntarily entered a California treatment facility for substance abuse following her March arrest where police discovered an unknown substance in her vehicle.The forty-four-year-old singer, who was stopped on the US 101 highway after reports of erratic driving, faces a May 4 court hearing as Ventura County prosecutors weigh formal charges.This decision follows a history of public struggles and marks a significant step toward recovery after she reportedly admitted to hitting rock bottom.