A star-studded fundraiser for Maryland’s marriage equality law is to be held in New York City next month.

John Waters, Susan Sarandon and former first daughter Barbara Bush are among those who are to appear at the event, which will take place on the roof gardens of the James Hotel, with tickets priced at $250.

Maryland – nicknamed The Free State – is one of four where marriage equality is on the ballot this year.

No state has yet upheld marriage equality at the ballot box, but extensive polling conducted by an LGBT rights group in Maryland showed that its inhabitants are open to the idea.

However, marriage equality is only one of four topical laws that Maryland voters will decide on. Others include expanding gambling, allowing some illegal immigrants to have in-state tuition and the congressional map.

Maryland’s Democratic Governor, Martin O’Malley, is channeling his energies into the marriage equality issue and will appear at the fundraiser alongside Edward Norton, Sarah-Jessica Parker, Julianne Moore, Josh Charles, Russell Simmons, Catherine Keener, Julianna Margulies, fashion designer Thom Browne, Bravo exec Andy Cohen and Gramercy Tavern founder Tom Colicchio,¬†among¬†others.

Gay former Republican National Committee chairman Ken Mehlman will also appear.