Mayor Michael Bloomberg said Thursday that he will preside over the marriage of his chief policy advisor, John Feinblatt, and his commissioner for consumer affairs, Jonathan Mintz.
The two have been together for 14 years.
The ceremony will take place at Gracie Mansion on July 24, exactly a month after Governor Andrew Cuomo signed the same-sex marriage bill into law.
Gay weddings are expected to pump millions of dollars into the city's economy.
Some venues are offering specials, and the Molly Blooms restaurant in Sunnyside, Queens is even offering one free same-sex wedding reception.
Meanwhile, New York Archbishop Timothy Dolan ramped up his advocacy against gay marriage.
The Catholic leader wrote on his blog that he fears the next step after gay nuptials will be a redefinition of marriage in order to justify multiple partners and even infidelity.
Dolan apologized for offending anyone, saying his stance is pro-marriage and not anti-gay.