A Michael Jackson Stamp? Maybe.

South Los Angeles (myFOXla.com) - The Rev. Al Sharpton will use an appearance at a South Los Angeles church Sunday to ask that a U.S. postage stamp be issued honoring Michael Jackson and call for a national day of mourning for him.

A stamp honoring Jackson cannot be issued until five years after his death, under criteria established by the U.S. Postal Service and Citizens' Stamp Advisory Committee. The only exception to the five-year rule is the issuance of stamps honoring deceased U.S. presidents, which are traditionally issued on the first anniversary of their birth that comes after their death.

The selection criteria also forbid the committee from considering issuing a stamp until at least three years after the subject's death.

The Postal Service receives up to 50,000 inquiries a year recommending stamp subjects and issues commemorative stamps on about 25 new subjects each year, according to its Web site.

A Jackson stamp could provide a financial boon for the Postal Service. The 1993 stamp honoring singer Elvis Presley is the best-selling U.S. stamp with 124.1 million sold, according to Postal Service figures, with many kept as souvenirs by collectors and fans instead of being used for postage.

Sharpton will issue the calls at a service beginning at 10 a.m. Sunday at the First A.M.E. Church, his publicist Rachel Noerdlinger told City News Service.