This is not a third movie, but rather a special in-character cast reunion to benefit the World Central Kitchen charity. It took place on September 25, 2020 on Netflix, Facebook, and YouTube at 11pm BST.
Most actors used their own own clothes, with some exceptions. For Steve Martin, Nancy Meyers bought and sent him dozens of sweatshirts that he tried on via Facetime. In the end, Martin "showed me an old one of his, and it was very George Banks. Steve later told me, 'When you asked me to do this I thought, this will be a pleasant two hours. Then we shot for four days and tried on sweatshirts for six days.'"
A third installment in the Father of the Bride series has been in development, in one form or another, since 1996.
The Zoom background used by Kieran Culkin was an image of Nancy Meyers's daughter's dining room. Culkin lived in New York at the time of filming, but his character is supposed to live in Los Angeles.
According to Kimberly Williams-Paisley, the remote filming experience "took an amazing amount of time to shoot this film given it was on Zoom. We had, like, tech scouts. I was driving Nancy around trying to show her different areas, different backgrounds. I was just carrying my computer everywhere and trying to find the right spot. Then I had a wardrobe fitting where I had to take her through my closet. She (Nancy Meyers) wound up sending me some stuff because I didn't have the right Annie Banks attire."