Walter Mondale, former vice president of the United States and U.S. Ambassador to Japan, and his wife Joan, member of the Citizens’ Stamp Advisory Committee, will lead a special first day of sale ceremony at noon May 11, for the new commemorative U.S. Postal Service (USPS) stamped envelope of legendary racehorse, Seabiscuit.

The Mondales will be joined by Winifred Groux, USPS San Francisco District Manager, and a San Francisco Bay Area woman who met and petted Seabiscuit in the winner’s circle.

Hosted by the Seabiscuit Heritage Foundation in cooperation with the USPS, the by-invitation-only ceremony will take place at the horse’s historic home and final resting place at Ridgewood Ranch in Willits, Calif.

Willits postmaster Dale Briggs will affix a special first day of sale postmark on the envelopes, which also will be available at the Willits Post Office