AC/DC’s Malcolm Young leaving band

Story highlights

AC/DC founder Malcolm Young won't be returning, band says

Young has been suffering from an undisclosed illness

His nephew, Stevie Young, will take over, band says

Group's new album is due out in December

CNN  — 

AC/DC founder Malcolm Young won’t be returning to the group, the band has announced.

The group’s new album, “Rock or Bust,” does not include Young. It will be released December 2, with a single, “Play Ball,” due to make its debut Saturday during the TBS postseason baseball campaign. (TBS, like CNN, is a unit of Time Warner.)

In April, the band revealed that Young was struggling with an undisclosed ailment. A press release said the illness was the reason he was unable to return.

“Unfortunately, due to the nature of Malcolm’s condition, he will not be returning to the band,” the statement said. “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.”

AC/DC’s Malcolm Young ill, ‘taking a break’ from band

The band hasn’t disclosed the nature of Malcolm Young’s illness, but one musician told an Australian radio station in April that the situation was “serious.”

Mark Gable told Australia’s ABC Radio that Young “is sick. … It’s not just that he is unwell, it’s that it is quite serious.” Gable’s remarks were reported at the time in The Sydney Morning Herald.

In July, lead singer Brian Johnson told Classic Rock magazine that Young was in the hospital.

“We miss Malcolm obviously. He’s a fighter. He’s in hospital but he’s a fighter. We’ve got our fingers crossed that he’ll get strong again,” Johnson told the magazine.

AC/DC is one of the biggest-selling bands in music history with more than 70 million albums sold in the U.S. alone, according to the Recording Industry Association of America.