Bono is taking medical advice, after he lost his voice during a U2 gig in Berlin last night.
It meant the show had to be cancelled after just a few songs.
The band said the frontman had been in 'great form and great voice' before the band's second gig in the German capital.
They said: "After a few songs, he suffered a complete loss of voice.
"We don't know what has happened and we're taking medical advice."
They apologised for the cancellation, adding that they'd offer an update on the situation soon.
The concert was just the second date of their European eXPERIENCE & iNNOCENCE tour, and they're next scheduled to perform in Cologne on Tuesday.
They are due to perform four sold-out homecoming gigs at Dublin's 3Arena in November.