Jason White, the touring guitarist of pop punk three-piece Green Day, has been diagnosed with tonsil cancer.
In a statement, the band told fans that they hoped he would "make a full and speedy recovery".
"We have some news to report regarding our brother Jason White, and wanted you to hear it from us before word spread," it read.
"Jason recently underwent a routine tonsillectomy, and his doctors discovered a treatable form of tonsil cancer. Thankfully they caught it early and he should make a full and speedy recovery. Please join us in sending him love and positive healing vibes during this time."
White first performed with Green Day frontman Billie Joe Armstrong in the early 90s, when he joined his side project Pinhead Gunpowder.