In the still photos that appear in the credits for Four Weddings and a Funeral, Fiona is pictured with her new boyfriend: Prince Charles. However, Richard Curtis told "USA Today" that in One Red Nose Day and a Wedding, Prince Charles is not meant to be understood as the father of Fiona's daughter, Faith, and that Fiona's involvement with the prince was more of a "fling rather than a long-term relationship. Fiona thought he didn't come up to scratch."
It's implied in the dialogue that Scarlett has died, or that she couldn't make the wedding due to living in America. This was due to the untimely passing of actress Charlotte Coleman in November 2001.
In the still photos that appear in the credits for Four Weddings and a Funeral, Matthew is shown happily celebrating with a new boyfriend. In One Red Nose Day and a Wedding, he introduces his husband, Anthony (Raza Jaffrey), clearly not the same man Matthew was dating in the end credits photo. The man in that photo was played by Duncan Kenworthy, who was a producer of the original movie. "USA Today" reported that because Kenworthy is not a professional actor, he didn't want a speaking part in this special, so they cast Jaffrey as Matthew's love interest.
Since the events of the first film, Bernard and Lydia have had six children, Laura continues to wear the ring borrowed from Scarlett, Tom and Deirdre are still together, as are David and Serena. Henrietta is on her third husband and Matthew is now married to a man named Anthony.
Faith makes a joke in her vows that she's glad she and Miranda aren't related like all her mom's friends. This is a reference to Fiona's best friend being her brother Tom and Tom's wife Deirdre being their second cousin's daughter.