Mason Lee plays alongside Bradley Cooper in the sequel, which follows four men on an alcohol-soaked odyssey through Bangkok, bagging nearly $186 million in two weeks in the United States despite sometimes harsh reviews.
"His performance is quite good, he is a very serious actor," Lee told reporters after watching the movie in Taipei, according to the Apple Daily newspaper.
But Lee said he had not thought about casting his son because the young man "should do whatever he wishes", he was quoted by the China Times as saying.
Lee is currently in Taiwan shooting his first 3D film "Life of Pi" about an Indian boy adrift on a lifeboat in the Pacific with a zebra, a hyena, an orangutan and a tiger.
The filmmaker, who is based in New York, was hailed as the "glory of Taiwan" after becoming the first Asian to win a best director Oscar for his gay cowboy drama "Brokeback Mountain" in 2007.