Indianapolis Mayor Greg Ballard, a Republican, and his wife Winnie attended the wedding of a gay couple.

Indianapolis City Council member Zach Adamson, a Democrat, repeated his vows to his husband Christian Mosburg during a multi-faith ceremony in Indianapolis last weekend after marrying in Washington, D.C. on October 19.

Adamson, who in 2011 became the city's first openly gay councilor, applauded Ballard for his “unwavering” support for marriage equality.

“I know he takes a lot of heat for it considering his party, so it did mean a lot for him to be there,” Adamson told NBC affiliate WTHR.

A spokesman for Ballard said that he was “happy to attend” the ceremony.

“It was a great day for Councilor Adamson and his husband and [Ballard] was happy to celebrate with them,” Marc Lotter said.

Indiana is expected to become a battleground state on the issue next year when state lawmakers decide whether to proceed with a proposed constitutional amendment which would define marriage in the state as a heterosexual union and prohibit civil unions as an alternative to marriage. If the measure gets the go ahead from lawmakers, voters will decide the issue next November.