Siblings Marlon, Tito, Jackie and Jermaine admitted that they have struggled to perform since the late King of Pop passed away in June.
"No matter what we're doing - working in the studio or rehearsing dance steps - there's an emptiness there. You feel it constantly. It's bearing down on you," Tito told The Mirror.
"Emotionally it's very difficult to sing these songs without Michael. Just to hear him on the radio today is very emotional."
Jackie added he struggled to accept that Michael had died when he was first told the news..
"Someone told me my brother was dead. It was very hard for me to believe," he said. "So I called my mother and she was screaming and hollering and crying."
"Michael was a major part of the Jackson 5 and of course he was a brother long before we became famous. I don't think people will ever understand the loss of Michael as a brother verses a pop star. Losing a sibling is devastating."
A previously-unheard Jackson 5 master recordings album was released in November to mark the 40th anniversary of the group's first number one single 'I Want You Back'.