In reality, Gloria Morgan Vanderbilt and her sister Thelma were identical twins. Lucy Gutteridge, who plays Gloria Morgan Vanderbilt in this TV movie, later played Thelma in The Woman He Loved (1988).
It was while Lady Thelma Furness was in America to support her sister during the trial that Wallis Simpson began her romance with Edward, Prince of Wales. Formerly, Thelma had been his mistress.
The mansion used for the exterior and interior set of this movie was Fulford Place in Brockville, Ontario, Canada. The house was designed by Albert W. Fuller, an American architect from New York, and built between 1899 and 1901 - having thirty-five rooms making up twenty thousand square feet. The Italianate gardens on the grounds were designed and built by the Olmsted Brothers. The house and grounds were fully restored in 1993, and the house is now a museum.
The cast includes four Oscar winners: Bette Davis, Christopher Plummer, Maureen Stapleton, and Martin Balsam; and two Oscar nominees: Dame Angela Lansbury and Glynis Johns.