The May issue of Astonishing X-Men #51, in which X-Man Northstar will propose to his boyfriend, Kyle, goes on sale Wednesday (23 May).
The storyline calls for the pair to be married in the following issue of the Marvel Comics series. Kyle does not have any superpowers unlike Northstar who can move and fly at supersonic speeds.
'The Marvel Universe has always reflected the world outside your window, so we strive to make sure our characters, relationships and stories are grounded in that reality,' Marvel editor Axel Alonso said in a statement.
The engagement issue comes out during the same week that rival DC Comics announced that one of its previously straight characters will be revealed to be gay in a forthcoming issue.
Northstar is a former mutant member of Alpha Flight and was the first character in the X-Men franchise to ever come out as gay. Northstar gains superhuman powers through his mutation and he uses them for the betterment of society.
Northstar first said the words "I am gay" in a 1992 issue of Alpha Flight #106 which sold out in a week. Previously, his apparent lack of interest in women was implied to be due to his obsessive drive to win as a ski champion.
But his sexuality was not focused on in the rest of the Alpha Flight series. It wasn't until Northstar joined X-Men as a regular in 2002. His relationship with Kyle, a sports manager at his company, was revealed in 2009.