Moyet was the special guest for the Tears for Fears performance at the town park's QEII Arena tomorrow.
The star sent a message to fans outlining her own disappointment at the developments.
She said: "I can’t begin to express how upset I am for those who’d hoped to see me.
"I have so longed to see you & have looked forward to these gigs tremendously."
She added: "Tears for Fears are a great band live & I know the show will be tremendous. I am truly sorry xxx."
The gig is part of a weekend of events at the venue, with Tom Grennan performing on Saturday before Bryan Adams takes to the stage on Sunday.