Glam-rock pop star and "American Idol" alum Adam Lambert is entering the Maryland marriage equality debate by headlining a fundraiser next week not in Maryland, but in D.C.

Lambert will perform Tuesday at the 9:30 Club at an event sponsored by Marylanders for Marriage Equality, an organization trying to get out the "yes" vote -- a vote in favor of same-sex marriage -- on Question 6 on this November's Maryland ballot.

Maryland Gov. Martin O'Malley applauded the 9:30 Club for hosting. "Question 6 is about treating every individual equally under the law, while protecting religious freedom at the same time, and we're proud to have the 9:30 Club join a growing list of businesses and coalition partners supporting Question 6," he said in a statement. We heard the governor might try to stop by the event.

Tickets for the Lambert fundraiser will go on sale Friday through ticketfly.com. They cost between $125 and $250.