Aiken, who is running on the Democratic ticket, became a household name in 2003 as runner up on "American Idol," and later appeared in the Broadway production of Spamalot in 2008.

The openly-gay performer turned his art into activism in recent years, taking on a UNICEF ambassadorship in 2004 as well as creating the National Inclusion Project and being appointed a two-year term on the Presidential Committee for People with Intellectual Disabilities. Aiken is currently running on the Democratic ticket in North Carolina's 2nd congressional district in his home state of North Carolina after winning the Democratic primary in May.

Members of the Broadway community will gather in New York City for an Oct. 1 fundraiser for Aiken's campaign.

"How exciting that a great voice on Broadway could become a great voice in Congress. We're all proud to support one of Broadway's own," Jujamcyn president and producer Jordan Roth said.

In addition to performances by Buckley (Cats, Sunset Boulevard), Ebersole (Grey Gardens, 42nd Street) and Leavel (The Drowsy Chaperone), the evening will be attended by Disney Theatricals president Thomas Schumacher, Rosie O'Donnell, composer Frank Wildhorn, director-choreographer Jeff Calhoun, director-choreographer Casey Nicholaw, producers Wendy Orshan and Jeff Wilson, and Playbill President and CEO Philip Birsh.

To attend the 7 PM event, visit clayaiken.com/broadway.