Eugene (Josh McDermitt) has already appeared in seven episodes of "The Walking Dead" since he was first introduced in Season 4, but viewers still do not know much about him, except for the fact that he claims to have figured out the cause of the zombie outbreak and a potential cure to reverse it. But in a new interview with McDermitt, he said that more of Eugene's backstory will be revealed this Sunday's episode titled "Self Help."

"We get to find out more about the scientific background that Eugene has," McDermitt, 36, told Access Hollywood.

In the Season 5 premiere, Eugene opened up a little bit about the cure. "I was part of a 10-person team at the Human Genome Project to weaponize diseases to fight weaponized diseases," he told Sasha (Sonequa Martin-Green) and the rest of the group while they were locked up in a train car at Terminus, according to The Walking Dead Wiki. "Pathogenic microorganisms with pathogenic microorganisms. Fire with fire. Interdepartmental drinks were had, relationships made, information shared. I am keenly aware of all the details behind fail-safe delivery systems to kill every living person on this planet."

He continued: "I believe with a little tweaking on the terminals in DC, we can flip the script. Take out every last dead one of them. Fire with fire. All things being equal, it does sound pretty badass."

McDermitt told Access Hollywood that Eugene decided to share that information to Rick's (Andrew Lincoln) group at that very difficult time because he needed more protection.

"The reason he kind of told Sasha and the rest of the group within the train car - it's like he needed that protection at that moment and said, 'The cure's gonna die with me,'" McDermitt explained. "But the longer he's with Glenn (Steven Yeun) and Tara  (Alanna Masterson) and Maggie (Lauren Cohan), along with Abraham (Michael Cudlitz) and Rosita (Christian Serratos), he's able to trust them more and I think we are gonna learn a little bit more about where Eugene is coming from with this cure."

But it is unlikely that "Self Help" will be all about Eugene's history.

"I think it's gonna kinda come organically,"  McDermitt told Wetpaint in September of how his character's backstory will unfold. "The writers do such a great job revealing things about people as we go along. What was so great about last season was that they had full episodes dedicated to just a couple of people and, that's cool, but I think the tone of this season is going be a lot more intense. It's pretty wild and it's gonna be a fun ride, so, I don't know that they're going just narrow it down and give Eugene his own episode."