The Big Sick is the sort of cinematic gem that comes around once every four or five years, says its producer Judd Apatow.
"It's just a very special movie," he tells The Straits Times at a recent interview in New York.
"Something magical happened in the making of that movie and it happens every once in awhile, where a group of collaborators have something they want to talk about passionately and everything falls into place and it works."
It is undoubtedly a hit now, garnering "best comedy of the year"type reviews as well as major awards buzz for its stars.
But Apatow reveals it was a struggle getting financing and distribution for the film, which tells an inter-racial love story that is atypical in Hollywood.
"We just worked on it for years with no sense of anyone having any interest in making it with us," says Apatow, 49, the comedy superproducer behind hits such as Bridesmaids (2011), the Anchorman films (2004 to 2013) and the television series Girls (2012 to 2017).
It was five years ago that stand-up comic Kumail Nanjiani, a Pakistanborn Muslim, and his wife Emily Gordon began writing a screenplay about their unusual real-life courtship and the obstacles they faced.
These included Nanjiani initially not telling his strict immigrant parents that Gordon was white, because they wanted him to have an arranged marriage with a Muslim woman. Then Gordon suddenly came down with a mystery illness and had to be put in a medically induced coma.
In cinemas now, it casts Nanjiani as a version of himself, with Zoe Kazan playing Gordon and Holly Hunter and Ray Romano as her parents.
Apatow, who wrote and directed The 40-Year-Old Virgin (2005) and Knocked Up (2007), spent about three years working on drafts of the script with Gordon, 37, and Nanjiani, 39.
At the time, the latter was starting to gain wider name-recognition from his role as a socially awkward software programmer in the acclaimed TV satire Silicon Valley (2014 to present).
They ended up making the film independently, outside the studio system, and then showed it early this year at the Sundance and South by Southwest film festivals, where it became a favourite with audiences.
When it debuted at Sundance in January, Amazon Studios outbid Netflix and several film studios for the North American distribution rights and gave it a limited release earlier this month at just five cinemas in Los Angeles and New York, where it earned an impressive US$87,000 (S$119,000) a theatre, the highest per-screen average for any film in the US this year.
As more people saw it and momentum began to build from all the glowing notices and positive wordof-mouth - the film has a 98 per cent score on review-aggregating website Rotten Tomatoes - it got a wide release.
"We were in two cities, then we went to 40 cities and now we're everywhere, and it's because people really like the movie," says Apatow. "And it's just a little US$6 million movie - we didn't even set it at a studio."
The film has collected more than US$28 million at box offices worldwide so far.
In addition, the story has acquired unexpected resonance in the wake of United States President Donald Trump's controversial ban on immigrants from certain Muslim countries.
"We didn't intend that," Apatow says. "We were just writing about an authentic immigrant experience in the US - here's what it's like to be here and deal with the culture you've been raised under, and what happens with your family and your parents as you try to adjust.
"And suddenly, because of the government's policies, the idea of showing a Muslim and Pakistani family seemed unique and humanising, and it had other implications. But it wasn't developed with any of that in mind."
Ultimately, the core of The Big Sick's appeal is that "it's a very sweet movie and it's really funny", he says.
"People have had a very strong emotional reaction to it. It's just a great story."
• The Big Sick is showing in Singapore cinemas.