George Young, and older brother of AC/DC guitarists Angus and Malcolm Young, died earlier this week at the age of 70.
"It is with pain in our heart that we have to announce the passing of our beloved brother and mentor George Young," said the pair in a statement. "Without his help and guidance there would not have been an AC/DC.
"As a musician, songwriter, producer, advisor and much, much more, you could not ask for a more dedicated and professional man. As a brother, you could not ask for a finer brother. For all he did and gave to us throughout his life, we will always remember him with gratitude and hold him close to our hearts."
They have not published a reason/cause of death