The incident happened while he was filming a scene for his action movie Black & White: The Dawn Of Justice, which opens here on Oct 9.
The movie also stars Chinese newcomer Lin Gengxin, Taiwanese actress Janine Chang and local actor Christopher Lee.
Chao, who was in town yesterday to promote the movie, told The New Paper: "The knife went straight into the flesh between my fourth and last finger on my left hand. I was rushed to the hospital and I received seven stitches."
The 30-year-old added: "When I returned on set, the director Tsai Yueh Hsun made me get back to acting immediately without any rest. This is how hard he worked us."
The new film is the sequel to the 2012 movie spin-off of the award-winning television police drama Black & White in 2009, which propelled Chao to stardom.
Chao's realistic portrayal of a rash, righteous and no-nonsense cop, Hero, saw him bag the highly-coveted Best Actor title at the 2009 Golden Bell Awards, Taiwan's equivalent of the Emmys.
Chao did not use any doubles for his fight scenes in the new movie at the request of the director.
The movie tells the story of how Hero (Chao), with the help of his intelligent but arrogant partner Chen Zhen (Lin), saves an entire city from being annihilated by a contagious deadly virus.
"I feel cheated by the director as he promised me that there would be stuntmen. However, on the day of filming, he told me that it would look much better if I did the action scenes myself," he said with a laugh.
"When we wrapped up filming, I felt that the stuntmen looked fatter than before as they didn't have to work so hard and were eating bento lunches all the time," he added jokingly.
"The director loves to torture me and see me in pain. I was bruised all over while filming the movie."
The heart-throb was in a good mood as he joked around with Tsai, 47, who was also here to promote the film.
Chao did not clam up when asked about his married life with Chinese actress Gao Yuanyuan, 34.
The couple, who started dating in 2012, registered their marriage in Beijing in June. They plan to register their marriage in Taiwan soon and will hold banquets in both countries.
Chao said: "We will hold it (the banquet in Taiwan) in the near future, but the date is not fixed yet. We hope to get married in Taiwan by this year-end."
The son of veteran Taiwanese singer-actor Allen Chao, 63, added: "Initially, we wanted a low-profile wedding, but I guess it is impossible. So, we will inform everyone when we are getting married."
In a press conference in Taiwan for the same movie on Tuesday, which was attended by most of the cast, Chao's co-star Lin Gengxin, 26, had teased him about not being a romantic husband to his new wife Gao.
Rebutting Lin's "accusations" during the sit-down interview with Singaporean media yesterday, a charming Chao gave a sheepish grin and said: "Gengxin is just jealous of me and my blissful marriage.
"I treat my wife really well."
This article was first published on Oct 2, 2014.
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