Two of Steve Martin's biggest movies of the '90s were the family comedies Father of the Bride and the sequel, Father of the Bride Part II, which made about $160M combined at a time when that was a pretty big deal. In the twenty years since there has been some talk of reuniting Martin and his co-star Diane Keaton for a third film, and now NikkiFinke.com says it's finally happening and addressing the gay marriage issue.
Martin will be returning as businessman and father George Banks, who has already married off his daughter in the prior films and is now facing the impending nuptials of his son, Matty, originally played by Kieran Culkin. George is unprepared for the news that Matty is gay and will be marrying the son of a Navy SEAL, and gets thrown out of the family home by his wife, Nina. Presumably this would mean Diane Keaton is returning, although neither she or Culkin seem to be confirmed just yet.
Charles Shyer, who wrote and directed the first two pictures, will be back after Nancy Meyers rejected an offer. This would be the first original movie in the series as the first two were remakes of 1950s films, Father of the Bride and Father's Little Dividend.