Adam Lambert is set to headline a fundraiser concert to benefit Marylanders for Marriage Equality, the group working to uphold a gay marriage law approved by lawmakers.

The concert will be held on Tuesday, September 25 at the 9:30 Club, the legendary live music club located in the U Street neighborhood of Washington, D.C.

“JUST ANNOUNCED! A benefit for Marriage Equality feat. @AdamLambert on 9/25! Tix on sale Fri 10AM!” the 9:30 Club tweeted.

“Marriage equality is about treating everyone as equals, regardless of who they fall in love with,” Lambert said in a statement. “I'm honored to appear at this event to help do whatever I can to bring notice to a cause that is close to my heart.”

Josh Levin, campaign manager for Marylanders for Marriage Equality, thanked Lambert for his support.

“As the campaign enters the final weeks, we're thrilled to have Adam Lambert's support of Question 6 in Maryland,” Levin said.

Seth Hurwitz, co-owner of the 9:30 Club and a Maryland resident, said that Governor Martin O'Malley had asked that the fundraiser be held at his venue.

“Although we historically don't get involved in political causes, on this issue I cannot stand by,” Hurwitz said. “People's personal opinions should not affect fairness and equality for all.”

Tickets, which start at $125 and go up to $250, go on sale Friday through or at the 9:30 Club.

(Related: Fun's Jack Antonoff, Andrew Dost committed to helping gay marriage.)