Warning: This post contains spoilers for The Walking Dead: Dead City season 2 finale.

Hilarie Burton‘s surprise return to The Walking Dead universe earlier this month wasn’t easy to film.

“Please forgive me if I get upset,” Burton, 42, exclusively tells PEOPLE of reprising Negan’s wife Lucille on TWD: Dead City‘s June 15 episode. “I just watched it. I didn’t see it on Sunday. This was a really hard episode to shoot.”

In the episode, Negan (Jeffrey Dean Morgan) hallucinates his dead wife after sustaining a head injury.

In a brief conversation, the usually tough-as-nails leader lets down his guard. Visibly upset, he apologizes for failing to keep his cancer-stricken wife alive.

Burton, also Morgan’s real-life wife, says that all the emotion fans witnessed between their characters was real.

“What people didn’t know is that, throughout this season, Jeff’s dad was dying. He had died like six days before we shot this scene,” Burton says of filming the scene last July. “Watching this man that I love so much hold that grief and really have to focus at work and hold it together, I wouldn’t cry except I just watched it.”

“It was really, really amazing to watch the person you love most in the world be able to do that,” Burton, who has been with Morgan, 59, since 2009, adds of filming their scene together. “He was able to channel a lot of the grief he was feeling for his dad into this episode while not letting anyone down.”

Morgan’s father, Richard, died July 2 after a brief illness. Burton says the Walking Dead spinoff crew, whom she previously worked with on White Collar, gave him a couple of days off from filming so the family “could go say goodbye to his dad” in California.

“It really was a family affair,” the One Tree Hill alumna says. “Everyone knew that he was dealing with this tragedy, but these storylines had been written well in advance. We had no idea when we got the news that his dad was sick that we would have to film this scene within days of seeing him for the last time. And we definitely had no idea this episode was going to air on Father’s Day. It was a lot.”

“I wish people knew what was going on behind the scenes when they see someone’s work,” Burton says of sharing such a vulnerable moment. “Anybody who’s in this line of work is usually tapping into something hard. The thing he was tapping into was really hard, but also very fresh. Working when you’re raw like that is a special skill set.”

She and the crew weren’t the only ones to offer Morgan support. Burton and Morgan’s two children, George and Gus, were also on set. Burton says their oldest, Gus, 15, an aspiring actor who now towers over his parents, showed up in a big way.

“Our kids were there with us and in his trailer hanging out, so he could just be silly with them in between every take,” Burton says. “Even when I wrapped, our son stayed with him at work and just shadowed the director and got to hang out with the camera crew. And so the balm that eases loss like that is being surrounded by the people who are still here and that we get to love on. Our son stepping up and being there for his dad at work was also a very cool turn of events.”

Could Lucille return to Dead City again?

While a third season of Dead City hasn’t been announced, Burton hopes fans will get to see more of her character.

“Anytime Jeff asks me to do anything, the answer is always yes,” says Burton. “He pushes me in a good way. And I really like that group of people. We’ve been with them for so long that it’s always a nice reunion.”

On Sunday’s season two Dead City finale, fans get to see a bit of the old Negan return. In a throwback to the controversial season six finale, Negan starts reciting “Eeny Meeny Miney Moe” before bashing in Bruegel’s (Kim Coates) skull.

“He definitely loves old Negan, and so do I,” Burton says of her husband getting to revisit the iconic moment on Sunday’s episode. “I’ll never forget laying in bed when he got the script for this part that wasn’t named Negan — It was all secretive at the time. And he knew exactly who it was, and he knew that he wanted to do it, and he was so excited to be bad.”

Burton says the overwhelming fan response to Glenn’s death in season seven was tough on their whole family.

“I think it was hard on all of us because we went from being able to be anonymous out in public to everyone recognizing him and also being really, really angry with him,” Burton says, adding it wasn’t all bad. “There’s a silver lining to it in that anytime my kids have an issue at school, he’s really great to bring into those meetings. He doesn’t have to say anything. He’s just kind of a scary guy now.”

Burton hopes viewers get to see more of “old Negan” moving forward.

“I think Negan has been on a grief and mourning tour for a long period of time,” Burton says of Negan’s redemption arc that played out in later seasons of The Walking Dead. She adds that pep talks from Lucille and Negan’s current wife Annie (Medina Senghore) on Dead City reminded him: “You’re not a villain.”

“That was an important moment that gives him permission to move forward,” Burton says, adding, “I think Negan is hilarious and really dynamic to watch when he’s at his worst. Lucille will continue to haunt him and hopefully pop up whenever he needs a pep talk because I like him bad.”