The chart-topping Britpop band are will headline the first performance of a series of music events at the Piece Hall on Saturday, August 28.
However the group confirmed on its Facebook page that two of its founding members - drummer Alan Leach and guitarist-keyboard player Joe Johnson - have decided to take an indefinite break.
However, they will not be departing until after their summer shows which includes the one in Halifax.
On a statement on their official site, the band said: "We are sorry to announce that for personal reasons both Alan and Joe have decided to take an indefinite break from Shed Seven following our upcoming festival dates.
"We remain good friends and respect their decisions. We would like to thank them both for the many years they have spent playing with the band and wish them all the best.
"Rick, Paul and Tom remain fully committed to Shed Seven and Shedcember 2021 and are looking forward to rehearsals, taking the show on the road and then seeing what lies beyond….
"We will let you know who will be joining us on the forthcoming tour very soon."
Formed in 1990 Shed Seven have 15 top 40 singles and four top 20 albums to their name, most recently reaching the UK top 10 with their latest album Instant Pleasures in 2017, marking a triumphant return for the band.
Joining Shed Seven on this Yorkshire -only bill will be platinum-selling indie rockers The Pigeon Detectives, Leeds indie-legends The Wedding Present and local lads Skylights.
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