When actor Huang Xuan was shooting an advertisement earlier this year, he took a call from director Feng Xiaogang, a man who was once hailed as "China's (Steven) Spielberg" by the American magazine Newsweek.

"Mr Feng asked me if I had time to hear a story," recalls Huang in a recent interview with China Daily ahead of the Beijing premiere of Only Cloud Knows.

Then, over the course of the next 20 minutes, Huang－who starred in Feng's 2017 runaway hit Youth－came to hear about the story of an enduring 36-year-long romance between a couple of close friends of the famous director, Zhang Shu and Luo Yang.

"I met Mr Zhang when I was shooting Youth. But this was the first time to learn about his past and suffering. Feng is such an excellent storyteller that his detailed depictions quickly stirred my emotions and brought a tear to my eye," recalls Huang.

Both natives of the Chinese capital, Feng shared a dormitory with Zhang when they worked together in an art troupe of the People's Liberation Army in the early 1980s.

Back then, most people were reluctant to talk about romance, but Zhang soon asked Feng for advice after confessing to falling in love with Luo at first sight on a bus ride.

The couple later married and emigrated to Canada. Zhang returned to Beijing in 2003 to work on Feng's film, and stayed for over a decade. Unfortunately, Luo was later diagnosed with cancer and passed away in Toronto in 2017.

Widely regarded as a front-runner who helped to propel the Chinese film industry with his stylish comedy blockbusters like The Dream Factory (1997) and Cellphone (2003), Feng in recent years has adopted a more personal and nostalgic approach as seen in movies like Youth.

Feng was moved when Zhang opened up about his feelings for his late wife, especially as he had just happened to catch iconic Japanese actor Ken Takakura's last film Dearest－a story about a retired prison warden who fulfills his dead wife's last wish－which also tugged his heartstrings.

All these elements helped give rise to Only Cloud Knows, his latest movie currently on release in China, New Zealand, Australia, North America and the United Kingdom.

Penned by novelist-turned-scriptwriter Zhang Ling, whose 2009 novel Aftershock was adapted by Feng into a disaster flick of the same name in 2010, Only Cloud Knows by contrast has a narrative that unfolds at a much slower pace.

Set principally in picturesque New Zealand, the 132-minute film follows the story of a Chinese expatriate who travels over 15,000 kilometers to fulfill his late wife's wishes, returning some of her ashes to her hometown in China and scattering more into the sea at a whale-watching spot near in New Zealand.

Through a series of flashbacks, the story unfolds how the couple fell in love when they rented separate rooms in a Chinese woman's house in Auckland, and later, their painstaking efforts in setting up their Chinese restaurant in the small town of Clyde in southern New Zealand.

Huang, 34, stars as the grieving husband, while 27-year-old actress Yang Caiyu plays his wife. The new movie marks their reunion after appearing as the main characters in Youth.

Yang, whose father died of cancer two years ago, recalls that she could appreciate the sentimental tone of the movie from her own parents' love story.

"My mother's situation is much like the husband's in the film. They have both been left in the sorrow of loneliness halfway along life's path," Yang explains.

Both of the stars spent a long time preparing for their roles in order to convey the bittersweet romance and the characters' sense of isolation and loneliness as expatriates.

Since a number of Huang's lines were written in English, he recruited a native speaker to act as a voice coach to "force" him to only speak English for the entire duration of the shoot.

On the other hand, Yang studied in the United States and has a good command of English, so she devised a way to make herself sound like a novice speaker.

"I wrote the Chinese characters under the English lines on the script to make me pronounce each phrase a bit awkwardly. So my lines in the film came across as sounding quite 'Chinglish'," Yang smiles.

Both stars also received culinary training to help them perform their scenes in the kitchen at the restaurant owned by the protagonist couple in Clyde.

"I'm still a bachelor and I have yet to reach the same age as the character's age (who is depicted in the movie as being in his mid-40s). So I had to draw on my most mature and complex emotions to imagine the psychological state of this middle-aged man who had suffered the pain of his wife passing away," Huang says of his approach to the role that spans 17 years in the movie.

Despite facing the challenges of acting and language, Huang had some happy and unforgettable moments with a special "actor" named Blue－a stray dog the couple adopted in the film.

"I was surprised to see that a dog could be so smart to follow all the acting commands from the director … such as pretending to be weak and suffering from breathing difficulties," recalls Huang.

Yang adds: "The dog is a famous star in New Zealand and has appeared in several films and TV series. I was told that I should establish an intimate relationship with him (the dog is depicted as a key member of the family in the movie), so I always had some delicious sausages in my pocket."

By Tuesday the film had grossed around 110 million yuan ($15.7 million), outperforming Disney's epic Star Wars: The Rise of Skywalker but still overshadowed by the box-office takings from Donnie Yen's final action film, Ip Man 4.