Reverend Al is back (shocking!)

Reverend Al Sharpton is using his Sunday appearance at The First A.M.E. Church in South Los Angeles to call for a U.S. Postage stamp honoring Michael Jackson, as well as national day of mourning.

Sharpton faces a steep challenge in getting the stamp approved, as commemorative stamps cannot even be considered until 5 years after the subject's death, according to the U.S. Postal Service.

The only exception to the rule is for deceased U.S. Presidents, who have traditionally been honored with a stamp released on their birthdays, following date of death.

Releasing a commemorative stamp could be a financial boon for the Postal Service as Michael Jackson memorabilia has reportedly been selling in high volumes and in some cases for significantly higher prices after the music icon's passing.

The 1993 commemorative stamp for Elvis Presley became the best-selling U.S. stamp to date with 124.1 million stamps sold, according to figures released by the USPS. Many of the units sold were reportedly kept as souvenirs, rather than used as postage.