When a frothy romcom opens near the top of the box office at around $30 million its first weekend in theaters, it's not news.

But if (and probably when, as it's projected to) Crazy Rich Asians does it, it will be seen as a milestone for a Hollywood movie with an all-Asian cast in a contemporary comedy. So there's a lot riding on the movie, probably more than there should be, and the guy who created the characters and watched the movie evolve for five years is a bundle of nerves.

"Do I feel pressure? Excuse me, I'm just going to go jump out a window," said Kevin Kwan, who wrote the novel and sold the rights to Hollywood, and who has been deeply involved in efforts to bring the comedy to the big screen (he's executive producer). Kwan, along with Jimmy O. Yang and Gemma Chan, stopped in Philadelphia recently to talk about the movie.

"Right now, I'm just trying to focus on the day to day. I love the feedback from people who've seen it already and really responded to it.  But I do feel the pressure. I know the movie is a kind of lightning rod, and of course I worry that if if doesn't perform up to a certain level of expectation, there is the danger there won't be another [Hollywood] movie with an all-Asian cast for another couple decades,"  Kwan said, referencing The Joy Luck Club, which is  cited as the most recent such Hollywood movie — and it was released 1993.

Crazy Rich Asians is tracking to open at roughly $30 million, which is a nice number — comparable to the opening weekends of Notting Hill, My Best Friend's Wedding, and It's Complicated. Could go lower, could go higher, but there are factors working in the movie's favor, including — of all things — a thriller about a giant shark.

>> READ MORE: 'The Meg': Jason Statham vs. the giant prehistoric shark

Crazy Rich Asians follows the The Meg, which shocked Hollywood with a $40 million opening weekend (double its predicted haul). The movie (based on a novel by Philly native Steve Alten) was  made with Chinese money, features a joint Western/Chinese cast (Jason Statham, Bingbing Li, Winston Chao), and is part of a wave of internationalized movies that draw talent and money from all over and feed into the global distribution system (another recent example: The Rock's Skyscraper).

If movies can be made anywhere, the talent and the money can come from anywhere, and those movies can succeed everywhere (The Meg made $141 million worldwide), why worry about Hollywood  rules and metrics?

"I think it's entirely possible we're seeing a paradigm shift in how movies are made. I certainly had a front-row seat for it the last five years. No one had ever made a movie  like this before, with a cast this international, with Asian stars from around the world, an international crew, shooting in the jungles of Malaysia and in Singapore," said Kwan, who was born and raised in Singapore.

Kwan said his mission in writing the books was to introduce his home country to the rest of the world.

"What most people know about Singapore is that you can't chew gum, and it's where [American] Michael Fay was caned for spray-painting a Mercedes," Kwan said. The country was run for three decades by Prime Minister Lee Kuan Yew, who transformed the island from a third-world economy into a first-world financial hub, running the country in a stern paternal style that banned unflushed toilets (and also dissent). It's now among the most prosperous and best-educated countries in the world.

"My goal in writing these books was to present the contemporary Asia as I know it. Because when I go to Asia, I see amazing technology, dynamic countries, booming economies, and sophisticated people. Cultured people living their lives and kind of not caring what goes on on the other side of the Pacific. And I felt that life was not being portrayed," he said.

Kwan was born to a well-to-do family and was educated in the United States. As an adult, he  split his time between the two continents and cultures. His experiences inform the plot of Crazy Rich Asians, which follows American woman Rachel (Constance Wu) from Manhattan to Singapore, where her boyfriend, Nick Young (Henry Golding), grew up and where he will be best man at a wedding. She discovers that her boyfriend's family is stupendously wealthy, and that she's suddenly in the middle of a knotty drama related to their money and power.

The story invokes East/West cultural differences, and even differences among the many ethnic groups that constitute Singapore's populace — Chinese, Malaysian, Indonesian, and many others. These conflicts extended to the production.  Kwan, for instance, was initially determined to cast the movie in way that reflected the narrative of his book – the Youngs were longtime residents of Singapore with a specifically Chinese heritage.

But after auditioning 400 Chinese actors, he was still looking for his Nick.

"I was adamant at the outset that Nick has to be an ethnically Chinese Singaporean actor. But it was like 'Goldilocks and the Three Bears.' We looked at all these actors, and nobody was just right. Then Henry walked in, and we knew immediately he was the perfect guy. It forced us to look at our own goals and expectations and our preconceptions," Kwan said of Golding, who is Malaysian and biracial.

There was some blowback from disgruntled Asian actors when casting didn't align with the ethnic attributes of certain characters, but most of that criticism has been resolved.  Gemma Chan (who plays Nick's cousin Astrid) said the controversy grew from the heightened sensitivity that Asian actors have about casting choices.

"It's been problematic, the history of the way Asians have been treated — they're either completely ignored, or miscast or typecast or grossly stereotyped. That's where the pain and the hurt come from," said Chan, who is of Chinese descent and who was raised in England — roughly in line with the characters in Crazy Rich Asians, many of whom attended British boarding schools and universities.

Chan is thrilled to be part of a production that shows so many Asian characters doing so many different things — being heroic, being wicked, being funny, being mean, being in love.

"For me, the faces that I saw that were Asian on TV and film were so few and far between that even if they were stereotypes, I would latch onto them. It didn't matter to me. That's why this movie is so important. Because the range of characters is so broad, so exciting," she said.

Co-star Jimmy O. Yang, star of TVs Silicon Valley, who plays a party animal who throws a bachelor party in international waters, likes the fact that in a movie with so many Asian actors, nobody's there just to check some casting box.

"I think audiences are hip to that. They see a big movie with one Asian character, they know what that's about," he said.

"Big studios have not been willing to really push the boundaries," said Kwan, who is distantly related to ground-breaking Hollywood star Nancy Kwan (The World of Suzie Wong), and who remembers the era when Hollywood used to invest in diversity, creating stars like Kwan, Omar Shariff, and Rudolph Valentino. "There is room on screen for just the same five stories we see over and over, or the same Marvel characters. No offense."

He nodded toward Chan, who plays Minn-Erva in Captain Marvel.

"None taken," she said with a laugh.

Yang said being part of an all-Asian cast actually makes acting easier, more exciting.

"There's something so great about about just playing your character to the hilt instead of worrying: how am I representing Asians? Because that is the thought a lot of the time when you are the only Asian character on a show. When you're in a cast of Asians actors, and everyone is just doing their job, it's very liberating."