Aubrey Plaza knows what it's like to have a stalker.
ET's Katie Krause spoke with the 33-year-old actress and her co-star, Elizabeth Olsen, at the Ingrid Goes West press junket held at the Fairmont Miramar Hotel & Bungalows in Santa Monica, California, on Thursday, where they spoke about having online stalkers and filming together.
In Ingrid Goes West, Plaza plays a crazed social media stalker who moves to Los Angeles to befriend her Instagram obsession Taylor Sloane (Olsen).
"I had kind of an online Twitter stalker, kind of, person that was around," Plaza told ET. "This was a couple years ago and then I was shooting a movie in Seattle and we found out that that person had applied to be an extra."
"Did you get a restraining order?" Olsen asked. "I don't remember," Plaza replied.
"But it's fine. I'm fine," the Parks and Recreations alum added. "But yeah, there was something about, there was a lot of, like, weird, creepy messages about cats. I don't know what he was talking about. He really wanted to have dinner with me dressed as a cat or something."
The actresses also dished about having a blast on set, improvising certain scenes together, like when they drove through Joshua Tree and sang along to "All My Life" by K-Ci & JoJo.
"It was like an improvised dance-song number that we did," Plaza recalled. "We basically serenaded over and over again with K-Ci & JoJo and that was the first night that we started shooting, right?"
"That was our first, yeah," Olsen chimed in. "We shot this scene at the gas station before and then we did that that night."
"Yeah, every take was a magical different journey," Plaza described.
"It was really fun," shared Olsen, "I was like, 'Let's keep doing things like this and let's keep making each other laugh.'"
Ingrid Goes West opens in theaters on Aug. 11