The ACLU is lobbying for the gay couple on "Modern Family" to get married.
ACLU Action started a campaign to urge the show's producers to write a wedding episode for Mitchell and Cameron, fathers of an adopted child and one of three couples at the heart of the show.
The ACLU says it is appealing to the fictional family to draw more attention to the real issue as it awaits Supreme Court decisions on two important marriage equality cases.
"Mitch and Cam are a couple that America has come to know and love, and seeing them get married, and seeing the characters in the story grapple with their desire to get married, makes it real for a bigger part of America," said James Esseks, director of the Lesbian, Gay, Bisexual and Transgender Project at the ACLU.
Supporters are invited to "RSVP" to the wedding online. The ACLU plans to deliver the online "guest list" to the show's producers but said it had not yet contacted the show.
Esseks said the petition was a departure for the group, but that along with filing lawsuits, lobbying for bills or organizing ballot initiatives, the group saw public education and changing the culture as part of its mission. He applauded what "Modern Family" has done already for public perception of gay couples.
"It's a popular show, they're a lovable, very real couple, and it would be great to see them walk down the aisle," he said.
ABC referred questions to 20th Century Fox Studios, which did not immediately respond to a request for comment.
Show creator Steven Levitan tweeted a link to the campaign with a simple "Wow." Jessie Tyler Ferguson, who plays Mitchell, tweeted: "Love this! Thank you ACLU! Maybe once Prop 8 is overturned!"