TV Best of 2016 (Behind the Scenes): Girls gets cinematic for Marnie's capsule episode Allison Williams takes EW inside season 5's Marnie-centric 'Girls' episode co-starring Christoper Abbott By Ariana Bacle Updated on December 27, 2016 01:00PM EST Photo: Craig Blankenhorn/HBO Allison Williams took the spotlight in an especially cinematic season 5 episode of Girls that saw her character, Marnie, running into Charlie (Christoper Abbott, who was a recurring cast member on the HBO show until he left in 2013) and having a surprising, wild night with him. The half-hour, titled “The Panic in Central Park,” quickly became considered one of the show’s best thanks to Lena Dunham’s half-euphoric, half-heartbreaking script and the main actors’ charming performances as two former lovers reconnecting in a dreamlike version of New York. After the episode aired this past March, Williams called up EW to talk about what it was like acting opposite Abbott again, the challenges of filming underwater, and how this experience will affect Marnie. As part of our year-end coverage, revisit that story below. Click here for more Best of 2016 coverage. Allison Williams knows that her Girls character, Marnie, isn’t exactly everyone’s favorite because, well, people tell her that Marnie isn’t exactly their favorite. Because of that, she was a little worried about Sunday’s Marnie-centric episode. “At the last second, I got scared, because I thought, ‘What if people just aren’t interested in her?'” she tells EW. There was no need: After the half-hour aired, Williams received plenty of praise via social media for the capsule episode, which featured a special cameo from Marnie’s former love interest, Charlie (Christopher Abbott). Charlie hasn’t appeared on Girls since the series’ season 2 finale, but he said yes to returning after Lena Dunham told him about her idea for the episode, inspired by The Panic in the Needle Park (1971): Marnie runs into a changed Charlie after a fight with Desi (Ebon Moss-Bachrach), and the two end up going on an adventure around the city before she eventually finds out that he’s been using heroin. “Lena had someone very close to her die of a heroin overdose and she kind of modeled the behavior that Charlie exhibits off of some of the ways that this guy changed toward the end of his life,” Williams says. “That included speaking differently and having a different attitude and tattoos and all that stuff.” Marnie’s clearly confused by Charlie’s altered diction and new look, and Williams herself had some questions about what the actor playing him has been up to. “Doing scenes with him felt very familiar, and yet I had many of the same questions Marnie had,” Williams, who hadn’t seen Abbott since they last filmed together in 2013, says. “I just let her ask them, and I kind of kept myself out of it because I felt like all of it was probably useful to the dynamic that we had to portray.” Williams tried to keep Marnie out of it too, in a way. “I thought about how ferociously she was trying to turn off that very fundamental part of her, which is to assess what’s happening and analyze it and just think everything to death and try to make everything okay,” she says. “I think from the minute she decided to go on this adventure with Charlie, she began actively trying to turn that part of herself off.” She was successful: At one point, she scams a wealthy older man out of a healthy chunk of cash and doesn’t freak out when a nervous guy mugs her later on. In one of the episode’s more poignant scenes, she boards a boat with Charlie despite her reservations about taking a ride on a vehicle that’s not theirs. They end up kissing and falling into the water, where Marnie lingers. “I had no idea how hard it is to act underwater,” Williams says. “And it’s very hard to breathe so that you don’t have bubble boogers. There was a couple times that we did it, and they were like, ‘It was perfect, you just have two bubbles at the end of your nose the whole time.’ “ Williams’ segment underwater lasts about 20 seconds, so she wore weights on her feet and carried some in her hands to keep her body in one place. That proved to be difficult to juggle with acting out the emotions she wanted to depict. “I was trying to show someone who is trying to process but trying not to process at the same time, but also trying to decide if she likes it better down there,” Williams says. “And that’s a lot to do with your face in a couple seconds.” Although Marnie’s experience was undoubtedly a powerful one — she went home after and asked her husband for a divorce, after all — Williams thinks she’ll keep it to herself in future episodes. “It’s pretty clear that she’s just told everyone about the divorce,” she says. “The Charlie thing she keeps to herself. I think it’s one of those things where she’s like, ‘This needs to just be mine.’ “