TOKYO (Kyodo) -- Japanese actress Tao Okamoto said Tuesday that she has yet to "fully grasp" the reality and historical significance of winning the best actress award at the Cannes Film Festival alongside her "All of a Sudden" co-star over the weekend.

Speaking at a press conference at the Japan National Press Club in Tokyo together with Belgian-French co-star Virginie Efira and director Ryusuke Hamaguchi, Okamoto, who became the first Japanese actress to receive the honor, expressed hopes that it would encourage people to see the film.

The film, known as "Soudain" in French and set to premiere in Japan on June 19, is based on a book of letters about illness and death exchanged between a philosopher and an anthropologist.

It depicts a theater director battling cancer, played by Okamoto, and a care facility director, played by Efira, who form a deep friendship.

Hamaguchi, an Oscar-winning director, praised the actresses for not only being exceptional performers but "extraordinary human beings," saying the film succeeded due to the "emotional energy" the two constantly gave to one another.

"Even during filming I was moved by what they created, and I was moved again during editing and dubbing. At times it almost felt embarrassing how emotional I became," Hamaguchi said.

Both actresses praised Hamaguchi's distinctive approach to directing and his intense focus on actors the moment the camera starts rolling.

Hamaguchi won best screenplay at the 2021 Cannes Film Festival and best international feature at the 94th Academy Awards in 2022 for "Drive My Car," which depicts a widowed stage actor and director navigating waves of grief following his wife's sudden death.

During production for his latest film, an international collaboration involving Japan, Belgium, France and Germany, Hamaguchi said he was deeply struck by the French system, which enforces strict shooting hours, mandatory rest periods and overtime pay protections for film crews.

While those labor rules contribute to budgets roughly three times higher than in Japan, he suggested Japanese productions could improve working conditions by reducing the scale of projects while maintaining the same budget.

"Large-scale production can certainly create spectacle, but spectacle alone does not necessarily move people's hearts or change the way audiences see their lives," he said.