Congratulations to Barney Frank!

The 71-year-old Massachusetts congressman is marrying his longtime partner Jim Ready of Maine.

An aide to the Democratic lawmaker -- well known for his outspoken and liberal views -- tells NBC news the ceremony will be in his home state, where same-sex marriage is legal.

Legendary Congressman Barney Frank (D-Mass.) -- considered the most prominent openly gay politician in the U.S. -- will not seek reelection in 2012 and will announce his retirement in a news conference in his home state  Monday afternoon, RadarOnline.com is reporting.

Frank’s spokesman, Harry Gural, said in a statement that Frank -- who’s held office for more than thirty years --will meet with reporters at 1pm ET at Newton City Hall in Newton, Mass., to “formally announce and answer questions about his decision not to run for reelection in 2012.”

Frank, 71, has served in the U.S. House of Representatives since 1980 representing Massachusetts's 4th congressional district.

PHOTOS: Stars Who Have Come Out As Gay