I Now Pronounce You Chuck & Larry (2007)

Chuck owes Larry for saving his life in a fire, and Larry calls in that favour when red tape prevents him from naming his two kids as his life insurance beneficiaries. All that Chuck has to do is claim to be Larry's domestic partner on some city forms. But when an overzealous bureaucrat becomes suspicious, the new couple are forced to improvise as love-struck newlyweds, fumbling through a hilarious charade of domestic bliss under one roof.

Official website: http://www.chuckandlarry.com.au