AC/DC might actually say goodbye and hello at the same time.

Bassist Cliff Williams recently announced his retirement after 40 years with the Australian rock band. Williams said issues concerning other members of AC/DC led to his decision. According to The Sydney Morning Herald, his departure from the band takes place at the end of their current “Rock Or Bust” Tour. The publication cited his interview with Gulfshore Life as he talked about his plans to retire.

“It’s what I’ve known for the past 40 years, but after this tour, I’m backing off of touring and recording. Losing Malcolm, the thing with Phil and now with Brian, it’s a changed animal. I feel in my gut it’s the right thing,” Williams said. Thus, guitarist Angus Young would be the only member left from the band’s heyday.

Guitarist Malcolm Young left the band two years ago due to dementia, the publication recalled. Meanwhile, drummer Phil Rudd’s mounting trouble with the law has kept him in New Zealand. Suitable alternatives have taken over their respective roles, namely, Young’s nephew Stevie and Chris Slade, respectively. However, finding a right substitute for Brian Johnson seems harder.

The AC/DC front man took time off from the band during their current tour owing to health problems. Yet the singer has no intentions to retire anytime soon despite his hearing problem. Guns N’ Roses lead singer Axl Rose stepped in during Johnson’s hiatus in the face of fears at his appointment. Eventually, Rose proved skeptics wrong as he rocked the stage even while sporting a broken foot.

AC/DC has yet to confirm if Axl Rose would take part in their upcoming summer tour dates in the US. A recent podcast from Zoiks! Online focused on another singer who might interest the band. Former Cinderella lead singer and guitarist Tom Keifer’s name is on the list of singers who fans have kept an eye on as Johnson’s possible replacement. While Keifer is not about to leave his own band, he did say the opportunity to do so would be humbling and an honor. Hence, could his response be an open invitation to the band?