Top This: A Gay Ceremony on ABC's 'Brothers & Sisters'

May 11, 2008— -- After much anticipation on the set of ABC's "Brothers & Sisters," a wedding cake has arrived. The four-tier creation -- adorned with flowers and blackberries -- is locked in a freezer, out of sight from the curious cast members, who are wondering what the cake topper looks like.

Spotting a prop woman with the topper in her hands, Matthew Rhys -- whose character, Kevin, weds Sunday (10 p.m. ET/PT) in the show's Season 2 finale -- calls her over. "Is it a man and a woman?" he asks. Getting a closer look, Rhys smiles and says, "Oh, it's two men. Fantastic. There were jokes made that they wouldn't be able to find two men, so they'd have to doctor the woman by adding a moustache."

This is no typical TV wedding. It's a gay commitment ceremony -- the first same-sex union on American network TV between series regulars.

"It's all very progressive, evolved and about time," says Rhys.

"It's a milestone, and I was really quite pleased that I got to be a part of it," echoes Calista Flockhart, who plays Kevin's big sis Kitty.

The Walker family and guests have gathered in the living room to watch Kevin exchange vows with longtime beau Scotty Wandell (Luke Macfarlane).

Flockhart's character will officiate at the ceremony while her husband (Rob Lowe) ends up playing a key role -- significant because he's a Republican senator opposed to gay marriage.

During a break, Lowe waltzes off set. "It's pretty romantic in there," he notes, greeting his visiting kid brother, actor Chad Lowe, who explains, "I'm here to witness history."

When Rhys and Macfarlane finally arrive on set in their crisp suits and ties, the cast and crew let out a collective awwww.

There is much affection for the characters, who met at the start of the series. It is a sentiment shared by at least one show fan. Rhys tells of a letter he received from the mother of a gay son. She "took great strength in seeing Kevin interact with his mother, and how little of a problem it is for them," he says. "It was a lovely letter."