Williams and Dreymond met when they filmed the 2020 movie Horizon Line; PEOPLE confirmed they got married back this past June

Allison Williams knows all about falling in love on the set of a major motion picture.

Williams, who married the actor Alexander Dreymon back in June, spoke to her experience getting to know her husband when they first met on the set of the 2020 movie Horizon Line when she caught up with PEOPLE at a special screening of her new movie Regretting You on Wednesday, Oct. 22.

"It's that once you've worked with someone, you have seen all different sides of them," Williams says, when asked about being part of a relationship that blossoms on a film set.

"So by the time Alexander and I decided to explore the romantic side of our relationships, I had seen him grumpy, hungry, exhausted," she adds, with a laugh. "Like I knew what he behaved like at 4:00 a.m. at the end of a 18 hour shooting day. And that's all very useful information."

PEOPLE confirmed that Williams and Dreymon had quietly tied the knot on June 26, days after Williams referred to the actor as her "husband" in an interview with The Guardian. The couple share son Arlo, whom they privately welcomed in November 2021; they began dating after making Horizon Line, a survival thriller in which they portrayed a pair of lovers who attempt to fly a small plane together after their pilot suffers a medical emergency.

The actress told Entertainment Tonight at the Los Angeles premiere of Regretting You on Oct. 20 that she and Dreymon were "never hiding [their marriage] or keeping it a secret" before the news broke in June. "We just didn't make a press release about it." While Williams spoke with PEOPLE on Oct. 22, she said that the wedding "was just a private little thing for us."

"It was just the best," she adds.