"[Showrunner] Angela [Kang] called me and said that it was a possibility and they were kind of figuring out who the love interests were going to be. She said there were a few options, this was one of the options... she just said there was a few different [alternates]," Serratos said at San Jose Fan Fest.
Serratos didn't mention which characters were considered for Rosita's lover, but she was linked to both Eugene (Josh McDermitt) and Siddiq (Avi Nash) in creator Robert Kirkman's comic books.
The surprising new romance was introduced in 906, "Who Are You Now?," following a six-year time jump.
"[Producer-director] Greg Nicotero told me that I should probably spend a little more time getting to know you better," Gilliam said of learning about the new coupling. "I was like, 'Why is that?' He's like, 'You should just find out what she likes, what she doesn't like, things like that.'"
"Six years is a long time, and when you leave," Gilliam said, laughing and playfully tapping Anne actress Pollyanna McIntosh, "when you leave somebody behind after knocking them unconscious, you can only... hope the best moving forward."
The Episcopalian priest was first with Anne, formerly Jadis, before she attacked Gabriel when he discovered she was in clandestine contact with a group of outsiders.
"I think, for one, six years has passed, a long time has passed," Gilliam said when explaining the Gabesita coupling. "For another, how many options does she have? I mean, look around [laughs]."
"How dare you!" Serratos said incredulously.
"Also, let me mention how I love that the stigma has kind of changed, because Rosita was with like three guys within a very short amount of time — which I think is totally kosher — but the second one guy goes from six years ago to one girl to another, now you're starting to feel it, now you're starting to feel it!"
Gabriel assumes a story arc originally played out with Eugene, who in the comic books entered into a serious relationship with Rosita following a multi-year time skip during the post-Savior war era.
"That's been fun for us, playing with Father Gabriel and showing this new side of him. He has come a long way, and so has Rosita," Kang told THR when explaining the reasoning behind the new romantic pairing.
"A lot of the conversations Christian and I had about Rosita centered on how she feels she needs to be with a man she feels challenged by, and someone she has respect for. We felt it was a really interesting pairing. We're going to have a very interesting story with them moving forward as well."
The Walking Dead Season Nine returns Sunday, February 10 on AMC.