Brian Johnson, lead singer of veteran Australian rock group AC/DC, said on Tuesday he was “personally crushed” to give up touring due to his hearing loss, but vowed that he was not retiring and will continue to record with the band in the studio.

Johnson, 68, said in a statement that he wanted to explain why the band was forced in March to postpone 10 of its U.S. shows for its “Rock or Bust” tour this year. The British singer was replaced by Guns N’ Roses frontman Axl Rose for the rest of AC/DC’s European and U.S. shows. Johnson said he had partial hearing loss, which affects his performance onstage, and he was advised by doctors in March that he risked “total deafness” if he continued to tour in large venues. Johnson called it “the darkest day of my professional life.” “I am personally crushed by this development more than anyone could ever imagine,” he said. “Being part of AC/DC, making records and performing for the millions of devoted fans this past 36 years has been my life’s work. I cannot imagine going forward without being part of that, but for now I have no choice.”

AC/DC, known for its blazing guitars and full-throated vocals on songs such as “Back in Black” and “Highway to Hell,” was supposed to perform in U.S. cities in March and April. The shows have yet to be rescheduled, but are expected to take place later this year.

Johnson said he was not retiring and that he is able to continue recording in studios with the band. “I am hoping that in time my hearing will improve and allow me to return to live concert performances. While the outcome is uncertain, my attitude is optimistic,’ he said.