The film, about a party girl who feuds with her dead boyfriend’s mother, is based on a novel by Janet Fitch, which Amy Poehler recommended to Ms. Tamblyn 10 years ago. “It was a constant uphill battle all the way up to shooting it,” she said. “I understand who I am now in a larger way. I never really felt like I knew who I was as an actress.”
Mr. Cross joined her at the subway pole. They met at an awards show, they explained, then crossed paths again when Ms. Tamblyn was shooting a film in the East Village, where he was living.
“I gave my number to the P.A.s and said, ‘If she’s looking to find out anything about New York, she can give me a call,’” he said. She never called, but about a year later they saw each other on a plane to Shreveport, La., where she was shooting “Beyond a Reasonable Doubt” and he was doing “Year One.” They wound up at a bar where it was swingers’ night.
“We were like, ‘These people are so friendly and nice!’” Ms. Tamblyn said.
Their subway pulled into Rockefeller Center around 6:45. Ms. Tamblyn had a friend waiting outside Radio City Music Hall with jewelry. “Curbside delivery!” Ms. Tamblyn said, choosing a bracelet from one of the zippered plastic bags that an antique-jewelry purveyor named Carrie Imberman pulled from her coat pocket, as if doing a drug deal.
Ms. Imberman eyed Mr. Cross and deadpanned, “You’re wearing your fancy sweater.”
Arriving at MoMA just in time, Ms. Tamblyn hurried onto the red carpet, posing with her friend Amy Schumer and the film’s stars, Alia Shawkat and Janet McTeer. After the screening, more famous friends joined her for a party at Fishbowl, the arcade-themed bar downstairs at the Dream Midtown hotel.
Sandra Bernhard and Steve Buscemi caught up by an aquarium, while the comedians Jon Benjamin and Jon Glaser (collectively, the Fuggedabuddies) sat at a table made from a pinball machine. Blake Lively spotted Mr. Cross by the Skee-Ball lanes. “It’s a good way to break the ice,” she said, as he started bowling.
Ms. Tamblyn downed a crunchy rice ball and circled the room, dispensing hugs. Toward the back, she found Ms. Lively, Alexis Bledel and America Ferrera, her co-stars from “Sisterhood of the Traveling Pants.” Someone brought over a birthday cake (Ms. Tamblyn had turned 34 the day before), and the sisterhood sang as photographers snapped wildly.
The D.J. cranked up the music, and Ms. Tamblyn hopped on the dance floor, where friends, including Ms. Poehler, Abbi Jacobson (“Broad City”) and Jenna Lyons, were letting loose to “Thriller.” Even Mr. Buscemi joined in, like the weird uncle at a hipster-comedian wedding.
“I’ve been going since 7 in the morning,” Ms. Tamblyn said, exhausted and elated. It was nearing midnight. She was planning to pump again on the cab ride home.