Aslan is to release its first single since the death of Christy Dignam on Thursday.
Dignam passed away at the age of 63 last month.
The cover version of The Fields of Athenry, recorded during the COVID-19 pandemic, will be the last song featuring his signature vocals.
August 5th will mark a year since the band last performed together.
Guitarist Billy McGuinness told The Hard Shoulder it still feels very surreal.
"I'm just in from rehearsal, and even something as simple as a band rehearsal is very surreal," he said.
"Myself, Joe and Alan are up there, we're playing the Aslan songs but there's no Christy there to sing them.
"It's very, very surreal".
'A tribute to Christy'
McGuinness said they want this to be a tribute to Dignam and the fans.
"When we came back together two weeks' ago, we just decided to play the music," he said.
"A band needs to play otherwise it's not a band - so we decided to come together two weeks' ago.
"We got the instruments out and we were playing Aslan songs - and that threw us into a frame of mind of, 'What could we do now?'
"Something for Christy, as a tribute to Christy, and as a thank you to the fans for their 40 years of support".
He said the last piece they recorded happened to be The Fields of Athenry.
"I think it's an amazing vocal from Christy, as always... we had a habit of making cover songs our own and he's done the same with this.
"As it being the last Aslan recording with Christy it's very, very special to me, and to everyone else that has heard it".
Christy Dignam speaks at Pendulum Summit in the Dublin Convention Centre in January 2020. Picture by: NurPhoto SRL / Alamy Stock PhotoMcGuinness said while Dignam can never be replaced, the band will keep going.
"We're musicians, we've been doing this for 40 years, we have to move forward," he said.
"There's bills to pay, life goes on but we miss him.
"There's no way you could ever replace Christy, not in a million years.
"But myself, Joe and Alan have made the conscious decision to keep Aslan going and move forward," he added.
