"The [romantic] feelings certainly don't disappear," Buck told TV Guide. "It'll be interesting for people to see her first response to that [revelation] and how that will change over the course of the season as well."
The showrunner confirmed that the story of Deb's feelings for Dexter (Michael C Hall) will again be a season-long arc.
"As you'll see, she doesn't get around to saying that to Dexter," he revealed. "So in all these previous seasons, it was Dexter with the big secret - now suddenly Deb has the secret."
"It's sort of perfect," she teased. "I didn't want Debra to lose any credibility with the audience. I wanted the things we've claimed to be true about her to remain so, and Scott Buck and the team of writers and producers did a great job."
The new season of Dexter will premiere on Sunday, September 30 on Showtime. In the UK, the series airs on FX.