Jennifer Carpenter says she’s been awaiting the moment at which the seventh season of “Dexter” begins: When her character Debra discovers her brother Dexter Morgan in the act of murder.

“I have been looking forward to it,” she said at the TV critics’ summer press tour. “I’ve been very curious about how they would write it, and also testified about it. And it’s sort of perfect. I think all of the anxiety and stuff that I’m feeling as an actor is exactly where Debra is supposed to be.

“I didn’t want Debra to lose any sort of credibility with the audience,” Carpenter said. “I wanted the things that we’ve claimed to be true about her remain so, and I think [executive producer] Scott Buck and the team of writers and the producers did a great job where I don’t have to lie or shape shift anything to make it fit for the sake of the show.”

It also seems to be unfolding at about the time the show is in its second- to last season.

“Her finding out does sort of make an end game feel a little more palpable and imminent,” says series star Michael C. Hall. “I think the plan is to do this season and a final eighth season, and I think to really tell this story of the two of them negotiating their relationship in this new landscape requires about that much time.”

Hall says this particular twist “is without a doubt the most fundamentally game changing a development as we’ve had since we started telling this story. One of the things that we’ve always been able to count on is that Dexter’s secret is his own, and it’s not any more. It’s been so invigorating to play these scenes, to be preoccupied in ways that Dexter’s never been required to be preoccupied. And to, in the seventh season of the TV show, have that genuine sense is pretty remarkable, I think.”

Dexter plays Sundays at 9 p.m. on Showtime.