Watch out New York City denizens, your next morning commute could turn into a major spoil fest.

A “careless casting director” made a huge boo-boo this week while casually reading the script for the upcoming, highly anticipated Season 4 premiere of HBO’s “Girls,” allowing onlookers to catch a glimpse and leak the details.

[WARNING: This article contains spoilers ahead. Do not read on if you have not yet watched Season 3 of “Girls” or do not want to know the leaked information.]

As fans of the show know, the season ended with a giant cliffhanger: Lena Dunham’s character, Hannah Horvath, may give up her life in Brooklyn with her friends and boyfriend, Adam (played by Adam Driver), to attend the Writers’ Workshop at the University of Iowa.

According to the New York Post’s Page Six, the spies confirmed that “Girls,” or at least its leading lady, will indeed be moving to the Midwest.

“We all know in the Season 3 finale that Lena’s character gets into Iowa, but we didn’t know if she’d really go,” a source who saw the script told Page Six. “In one of the scenes, Jessa (Jemima Kirke) and Shoshanna (Zosia Mamet) are FaceTiming with Hannah (Dunham), and they’re in New York while she’s living in Iowa City.”

Page Six said the script was legit because multiple spies saw the papers had a watermark with the name, Tony Behringer of Central Casting, on it. According to the Post, Behringer is an agent who has cast extras for “Girls” before.

A rep for Central Casting declined to comment to the Post.

News of the big move to Iowa may come as a shock to fans who were informed last month that the University of Iowa would not welcome “Girls” to film on its campus.

Joe Brennan, the vice president of strategic communication at Iowa, told the Iowa City Press-Citizen it came as a shock when the show included the MFA program in its Season 3 finale, and the school decided to deny HBO the rights to film on-site.

“After reviewing the script, I felt the storyline placed the city and university in an unfavorable light, and considering the potential for disruption, I made the decision to deny the request,” Brennan said. “I won’t share details as I don’t think it fair to reveal the plot in advance. I understand this is a popular show, but it’s my job to safeguard the reputation of the university.”

HBO told The Post in response: “We cannot confirm any plot points or story lines … just because a scene may be set in Iowa doesn’t mean the cameras are actually in Iowa.”

While the Season 3 finale aired only last month on March 23, Season 4 of “Girls” began filming in New York City recently. The Post reported that Dunham was “spotted filming around town in her signature shorty shorts” with co-stars Kirke, Mamet, Driver and Allison Williams, who plays Marnie.

Dunham, who is the series creator, is rumored to be “courting” Taylor Swift to be a guest star on the show.