Don't be surprised if there's a few mascara tear stains on Liza Minelli's wedding dress -- the bride-to-be is reportedly crestfallen that Whitney Houston has reneged on a promise to sing at the marriage.

The New York Daily News said Houston called Minelli to break off her promise to sing for the star and her fiance David Gest. Despite Minelli's tears, Houston had to beg off a planned performance of "The Greatest Love Of All" so she could continue work on her new album in Florida.

The paper says Houston's spokesperson would only say that the singer wishes the couple well. The couple's representative would only say a terse: "David and Liza hope Whitney is well."

Natalie Cole has come to the couple's rescue. She'll perform "Unforgettable" as the couple ties the knot, the report said.