As U2 prepare to kick off their residency at The Sphere in Las Vegas later this month, they will be doing so without drummer Larry Mullen Jr. In a new interview, bassist Adam Clayton opened up about the band’s first shows without Mulle in over 40 years.

“The whole band and I’m sure the audience are going to be very sad and miss Larry,” Clayton told the Daily Star. “He wants to come back, he wants to be able to have a long career and continue his drumming so he’s taking care of those injuries.”

Mullen will not participate in the first round of shows for the ‘U2:UV Achtung Baby Live at Sphere’ residency due to a planned surgery to take care of lingering back issues. Instead, Dutch drummer Bram van den Berg from the band Krezip will fill his role.

“He’s very much behind the idea of us going on stage with Bram [van den Berg],” Clayton said. “I’m sure for Larry it’s a difficult moment to know that your band are going on stage and you’re not with them.”

This isn’t the first time someone has had to step in for an ill band member. Back in 2014, Bono was briefly unable to perform with the band, so a series of famous musicians stepped in to sing with U2.

“Bruce Springsteen stepped in which is quite a strange one as well. Actually, Chris Martin did a turn as well… It happens in the life of bands,” Clayton explained. “I think Larry is probably quite sanguine about it and realises he needs to get his health back together again.”

U2’s Las Vegas concert residency is set to kick off on September 29th.