Cast members of the movie visit Gong Quanzhen's home.[Photo provided to China Daily]

Gong, now 93, who was selected as a national role model in 2013, was honored by Chinese President Xi Jinping. She was also selected as one of the 10 winners this year in the "Touching China" awards, an annual event held by China Central Television.

Lei, an award-winning director, is known for his role model-themed films, including the 1996 commercially successful movie Life after Departure of Lei Feng.

But even though he has directed a number of role-model features over nearly two decades, the 61-year-old director says that the latest film was one of his career's biggest challenges.

"It took us three years and more than 30 script revisions before we made the film," he tells China Daily.

"This is because unlike Hollywood blockbusters, such movies cannot be too dramatic. And, we also had to work hard to make it appealing for present-day audiences."

Lei says he was very impressed while researching the lives of Gan and Gong.

"It's about how they stayed true to their hearts," he says.

"Gan became a Communist Party member in 1927 and joined the Red Army the following year. He was a veteran soldier who survived the Long March. But he had also promised his fellow villagers that he would return after the war," says Lei.