AC/DC fans are thunderstruck over the latest news. Reports are coming in that Malcolm Young, one of the founding members of AC/DC, was diagnosed with dementia and is being treated at the Lulworth House care facility in Sydney, Australia as his condition deteriorates.

A source the Sydney Morning Herald "If you were in the room with (Young) and walked out, then came back in one minute later, he wouldn't remember who you are. He has a complete loss of short-term memory. His wife, Linda, has put him in full-time care."

AC/DC released a statement earlier this year saying Malcolm would take a break from the band because of illness. It has since come out that, because of Malcolm's illness, he will not be returning to the band.

AC/DC put a statement on their Facebook page at the time, saying "After forty years of life dedicated to AC/DC, guitarist and founding member Malcolm Young is taking a break from the band due to ill health. Malcolm would like to thank the group's diehard legions of fans worldwide for their never-ending love and support. In light of this news, AC/DC asks that Malcolm and his family's privacy be respected during this time. The band will continue to make music. "

Young's nephew Stevie Young will play guitar in Malcolm's place.

"Stevie, Malcolm's nephew, was magnificent, but when you're recording with this thing hanging over you and your work mate isn't well, it's difficult. But I'm sure he was rooting for us. He's such a strong man. He's a small guy but he's very strong. He's proud and he's very private so we can't say too much," Johnson said.

AC/DC just announced that their new album, "Rock or Bust," will be released on December 2.

"Rock or Bust" is AC/DC's first album in their 41 year history without founding member Malcolm Young. 

Brian Johnson reportedly wanted to name it "Man Down" as a tribute to their founding guitarist, Malcolm Young.

"Rock or Bust" is AC/DC's first studio album of all new material in six years. It is the follow-up to their 2008 "Black Ice" album, which debuted at #1 in 31 countries and continued selling until it got to almost 8 million copies worldwide.

AC/DC will go out on a world tour in support of "Rock or Bust" staring in 2015.  Joining the band on tour will be the nephew of founding members Angus and Malcolm Young, Stevie Young. Young played rhythm guitar on "Rock or Bust."

"Rock or Bust" and features 11 new tracks. It was recorded at Warehouse Studio in Vancouver, British Columbia in Spring 2014. AC/DC returned to the studio with longtime producer Brendan O'Brien and mixer Mike Fraser.

AC/DC was put together in November 1973 by brothers Malcolm and Angus Young. They moved to Australia from Scotland in 1963. Brian Johnson replaced Bon Scott, AC/DC's original lead singer who died on February 19, 1980. Scott died of "acute alcohol poisoning" after partying all night at the Music Machine club in London. Brian Johnson joined for AC/DC's Back in Black album.