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When Kate Hudson shows up for a party, you know that it’s going to be a good time. On Thursday night, the actress—who appears on the cover of InStyle’s May issue—attended the New York City premiere of her new movie, Mother’s Day, and she took over InStyle’s Snapchat for the occasion. After sharing getting-ready videos throughout the afternoon, Hudson finally revealed her outfit for the night: a gorgeous Valentino gown. “In love with this dress,” Hudson captioned a selfie while en route to the premiere.

As Hudson was making her way to the event—which was hosted by Cinema Society, Fiji Water, and Lands’ End—stars began to hit the red carpet at the retro-inspired Metrograph Theater. Olivia Palermo (below, left) posed for photos while mom-to-be Nicky Hilton (below, right) perused the many candy offerings, and Aasif Mandvi—who plays Hudson’s husband in the film—revealed what it was like to find out that he’d be starring opposite Hudson on the big screen.

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“Our director, Garry Marshall, didn’t tell me I was going to play Kate Hudson’s husband at first,” Mandvi (below) told InStyle. “Instead, he called me and said, ‘I know you like peanut butter, and there will be lots of peanut butter on the set.’ So I’d already been enticed with all the peanut butter—and then later, he told me I’d be playing Kate Hudson’s husband. I was like, that right there is what you should have opened with—forget the peanut butter!”

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Once Mandvi learned that he’d be working with Hudson, the co-stars decided to have a bit of fun with their roles. “Kate and I did our own sort of PG-13 slash X-rated version of Mother’s Day that ended up on the cutting room floor,” said Mandvi. “I played it Stanley Kowalski-Al Pacino, and she played it like a Southern belle. We had all these scenes that would just make us laugh, but they never ended up in the movie.”

That was probably a good thing for the pair’s co-star, Jack Whitehall (below), at last night’s premiere. “I brought my actual mom tonight so that she can see the film,” the Burberry-clad British actor told InStyle before heading into the screening. “She watches a lot of the things I do even though they’re not really aimed at her—it’s quite a lot of puerile comedy. So hopefully this will be more on her level.” The movie is certainly kid-friendly—just like Whitehall’s co-star Britt Robertson, who plays his girlfriend in the film. “We had some babies on set, and she was very good with them,” he said of Robertson. “She’s like a mother in waiting.”

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Robertson wasn’t the only one to receive rave reviews for her natural touch with little ones on set. The film’s legendary director, Garry Marshall, had nothing but praise for Hudson’s parenting skills—especially since he’s known her since she was a child herself. “She ran around on my set during Overboard,” Marshall said of the 1987 film starring Hudson’s mother, Goldie Hawn. “But on this set, she was there doing great—and her kids were running around.” Marshall’s witnessed Hudson’s motherhood journey since day one, he revealed while reminiscing their 2004 film, Raising Helen. “One day [during filming] she was feeling sick,” said Marshall. “I said, ‘You don’t look that sick.’ Then I whispered and said, ‘Are you pregnant?,’ and she said, ‘Yeah.’ She had [her son] Ryder at the end of that film.’”

The close bond between Marshall and Hudson was apparent after last night’s screening, when the Mother’s Day cast hit the after-party at Ladurée Soho. Guests munched on sliders, French fries, and macarons in the restaurant’s outdoor garden while beats like Sia’s “Elastic Heart,” Calvin Harris’s “How Deep Is Your Love,” and Charli XCX’s “Boom Clap” played overhead. Hudson chatted with Marshall, telling him “I love you, Garry,” before sipping on cocktails at her table with a group of friends that included jewelry designer Jennifer Meyer.

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Midway through the party, Hudson’s Raising Helen co-star John Corbett (aka Aidan from Sex and the City) arrived. Looking casual in a leather jacket, Corbett (above, right) spent time catching up and posing for photos with Marshall (above, left) before heading over to Hudson’s table. Clearly excited to see each other, the pair spent the rest of the night talking, hugging, and laughing until well after many of the guests headed out for the night.