"True Detective" marked HBO's biggest debut since "Boardwalk Empire" in 2010, and when it returns for its second episode Sunday night (January 19), not only will viewers get more of the pitch-black murder mystery and great performances from Matthew McConaughey and Woody Harrelson, but they'll see Alexandra Daddario take on her most mature role to date.

The actress is known for her roles in the "Percy Jackson" series and the most recent "Texas Chainsaw Massacre," but on Sunday's episode, "Seeing Things," Daddario takes on a part that she described to MTV News as a "huge challenge."

As Lisa Tragnetti, Daddario plays the young woman who has an affair Detective Hart (Harrelson), and after just a brief appearance in the first of eight episodes, her role greatly expands in the second. Speaking with MTV News, Daddario recalled her decision to take on the role and how she approached her revealing scenes with Harrelson.

"I think one thing about this role for me was that it was a huge challenge for me, and I saw it as a good challenge. I saw it as an interesting challenge," Daddario said. "I really wanted to be part of the show, and I understood why the nudity and all of that was required of the character.... The character is really different from anything that I've done before. The nudity was just part of that."

On the day of the shoot, Daddario took comfort in her more costar, whose experience helped her through a situation that could have been awkward.

"Woody has done so many different things. He made the whole situation very comfortable," Daddario said. "It wasn't anything awkward in that sense. I tried not to think about it too much before shooting the more intimate scenes and just sort of did it. [Harrelson] has been there done that. He's Woody Harrelson. If there's anybody that I was going to be comfortable with, it's somebody like him."

"Seeing Things" only just started to tell the story of Lisa in the context of Hart's life, and Daddario says that there's likely some trouble coming from the relationship.

"I think she's definitely got some issue. Nobody is all good or bad," Daddario said of her character. "If anything, she is probably a little bored and emotionally volatile and naïve. She has probably done things like this before, maybe not exactly how it all turned out. That's her role in Hart's story. She causes problems for him."