Most of the talk about HBO's hit half-hour comedy, Girls, is naturally centered around the show's creator, writer, producer and director, Lena Dunham, 25, but as new episodes are let out of the bag week to week (Sunday's episode number three), new questions arise for Dunham's co-star, Allison Williams.

Allison, the daughter of NBC's Nightly News anchor Brian Williams, plays Marnie, the best friend and roommate of Dunham's character, Hannah. In the most recent episode to air, Marnie — who has been suffering through a boring relationship with her milquetoast sweetheart, Charlie, played by Chrisopher Abbott — finds herself so aroused by a fellow party-goer that she runs to a public restroom to, er, relieve herself. Given Allison's relationship with her famous dad, it's fair to wonder if there was any extra awkwardness surrounding that scene.

Not really, Allison said. "A scene like that just gets added to the pile and gets smushed in," she told HuffPost TV about her character's most NSFW moment yet … and hinting at more to come.

More content that is adult, gritty, embarrassing — whatever you want to call it — will likely only satisfy fans of Girls, who praise the show's less-than-glamorous depictions of four women in their early 20s living in New York City. "That's my life," Williams said, vouching for the show's authenticity. "It's so grounded in reality that it almost feels like a real show. But we are acting, which is an important detail."

And how did Allison find her match with Girls? Good question. In 2010, a YouTube video called "Mad Men Theme Song … With a Twist" featured Allison, then 21, singing the lyrics to "Nature Boy" while an orchestra played the tune to Mad Men's opening number. The clip somehow landed in front of Judd Apatow, who was at the moment producing the pilot for Girls, and apparently he was smitten.

"I guess he saw something in my performance that kind of rung true with Marnie," Williams told The Hollywood Reporter. "I can kind of understand that now. There's a sort of cleanliness to it that's consistent with Marnie. He contacted [my agent] and said to make sure I got the script, which was a lot of pressure. Not only did I have to worry about disappointing myself, I might disappoint Judd Apatow."

Disappointed he was not. But getting the role of Marnie, the first that Allison had auditioned for since moving to Los Angeles, meant trucking back to New York City, where Allison had lived since graduating from Yale University in 2010. "It was very funny having to pack my stuff back up after very dramatically moving out there," she said.

A "very funny" and "very dramatic" approach to the mundane-yet-terrifying challenges of being in one's early 20s? Yup, sounds like Allison is right at home in Girls.

Watch Allison in that 2010 YouTube video here: