A new headline act is being sought for the Mouth of the Tyne Festival after the Lighthouse Family pulled out.
The duo, who formed in Newcastle in 1993, were due to perform on Saturday 9 July but announced they were no longer touring or making music.
Keane, Eliza Shaddad, Sophie Ellis-Bextor and Newton Faulkner are still set to perform on the remaining nights of the three-day event in Tynemouth.
Organiser North Tyneside Council said ticketholders could get refunds.
The Mouth of the Tyne Festival has been running since 2005 and attracts more than 100,000 people but was cancelled for the past two years because of Covid.
North Tyneside Deputy Mayor Carl Johnson said: "We were extremely disappointed to hear that the Lighthouse Family are no longer performing together and will be unable to play their headline slot at the Mouth of the Tyne Festival.
"A sell-out audience have held on to their tickets throughout the pandemic, and like us, they were looking forward to the performance.
"However, the decision to pull out of the show has been made by the band leaving us all bitterly disappointed."
The Lighthouse Family formed in Newcastle when keyboardist Paul Tucker and singer Tunde Baiyewu were students in the city. They parted company in 2003 after a string of 90s chart hits like High, Ocean Drive and Lifted but reformed in 2010.
In 2019 they released a new album - their first in 18 years - and announced a new tour but their time together has once more come to an end.
Tucker said: "I have tried everything with our agents and promoters over the last few weeks to make this work but we just couldn't get it over the line.
"Tunde now wants to focus on his solo career and I wish him all the best. I would like to say sorry to the promoters and to all of you who have tickets for this show and have waited through the last two years.
"I was really looking forward to this hometown show and playing our songs in this amazing place close to the lighthouses that gave us our name. I am as disappointed as you are. It breaks my heart to let you down."
Brit Award winners Keane will headline the Friday night with special guest Eliza Shaddad, while Sophie Ellis-Bextor and folk guitarist Newton Faulkner will perform on Sunday.
Mr Johnson added the council was "exploring all avenues" to get a new headliner for the vacant Saturday slot.