The singers were just about to start rehearsals for the festive Beacon Theatre show in New York City when they learned they were no longer required.

A source tells Page Six many of the choir's members had "adjusted their professional and personal schedules to accommodate the set gig".

The choir's lawyer has fired off a letter to Carey's aides, calling the termination unacceptable.

Mariah performed nine sold out shows at the Beacon Theatre earlier this month (Dec16).