It’s been an incredible 40 year career for the legendary Australian rock band AC/DC. Over that time they’ve released fourteen hit studio records, and they have just announced their 15th, titled Rock or Bust, will hit stores in the U.S. on December 2.

Unfortunately, it will be the first one they’ve recorded without founding member and rhythm guitarist Malcolm Young.

Back in August, the band’s biographer Jesse Fink, claimed that Young was in ill health and suggested he would not be returning to the band as they record their first new album in six years. Today, the remaining members confirmed both the exciting and somber news in a statement through their management firm Alberts Music.

“Rock or Bust” is the first AC/DC album in the band’s 41 year history without founding member Malcolm Young on the recordings,” read a statement on the band’s website. “Earlier this year AC/DC released a statement explaining that due to illness, Malcolm would be taking a break from the band. Unfortunately, due to the nature of Malcolm’s condition, he will not be returning to the band. AC/DC will undertake a world tour in support of ‘Rock or Bust’ in 2015. Stevie Young, nephew of founding members Angus and Malcolm Young, plays rhythm guitar on ‘Rock or Bust’ and will accompany the band on tour.

The band have not disclosed the nature of Young’s illness and refuse to do so. Fink also declined to offer any other information about the guitarist’s current condition.

“I think the important thing is we all let Mal be and hope he can recover,” said Fink to a US radio station last month. “As far as I’m concerned, Malcolm’s illness is a private matter.”

As for the new album, it was recorded in Vancouver, and once again reunites them with long-time producer Brendan O’Brien. There are 11 new tracks, among them, Play Ball, which will be used as part of Turner Sports 2014 Major League Baseball Postseason campaign.