Michael Bolton is sharing new details about a somber health diagnosis he’s been navigating over the last year and a half.In a new interview with People, the singer revealed that he has glioblastoma, a form of brain cancer that the Cleveland Clinic defines as the “most common type of malignant (cancerous) brain tumor in adults.

Michael Bolton exclusively opens up to PEOPLE in this week's cover story about facing his glioblastoma diagnosis and facing brain cancer with his family by his side and sense of humor intact.