Online videos show the `` Rehab '' singer unable to sing in Belgrade . Winehouse representative Tracey Miller did not directly confirm that the `` Rehab '' singer , who has a history of battling drugs and alcohol , had fallen off the wagon . The Serbian government has said it will not allow her to perform at a concert on June 8 because she is suffering from an unspecified illness. Winehouse entered a rehab program last month to prepare for the tour .
Online videos show the `` Rehab '' singer unable to sing in Belgrade . The Serbian government has said it will not allow her to perform at a concert on June 8 because she is suffering from an unspecified illness. Winehouse entered a rehab program last month to prepare for the tour .