HONG KONG - Leon Lai is now a Heavenly Dad, say Hong Kong newspapers.

Rumours circulated on Monday that the pop star and his assistant Wing Chan had recently and quietly welcomed a premature baby girl, weighing only about 2.3kg, reported Apple Daily.

Lai, 51, had confirmed the pregnancy of Chan, 32, a month ago. He said on Facebook they were "two people who have experienced divorce" and got together. He did not mention whether he had married her, but said he would protect his family members against media exposure.

Following rumours of the birth, fans left congratulatory messages on his social media sites, but he and his friends kept mum, said Ming Pao Daily News.

His friend, composer Mark Lui, said he did not know of the baby's arrival. "If it's really a premature birth, he should be so busy that he could vomit," he told Apple Daily. "He wouldn't be free to notify me."

Lai is the last of the four Heavenly Kings to become a father. Aaron Kwok welcomed a daughter in September. Andy Lau's daughter is five years old. Jacky Cheung's two daughters are 12 and 16.

Seeing that all the four stars are raising princesses, Hong Kong newspapers have dubbed them the "Four Fathers of Brides".