Tinglan Hong and Hugh Grant have welcomed their second child together, a baby boy named Felix Chang, according to The Mail On Sunday.

Tinglan Hong, the mother of Hugh Grant’s 16-month-old daughter Tabitha, gave birth on December 29 and registered the new arrival on Valentine’s Day.

According to the birth certificate, Felix Chang was born at St Mary’s Hospital in Paddington, West London – where Kate Middleton is expected to have her child.

The boy’s full name is Felix Chang Hong Grant. Felix is the Latin word for lucky and Chang in Chinese means long-lasting.

It is understood Hugh Grant told his closest friends only in the last week, but swore them to secrecy. His ex-girlfriend Elizabeth Hurley, who is godmother to Tabitha, was among those informed.

Hugh Grant decided to make the news public yesterday on Twitter.

At 3.19 p.m., Hugh Grant posted a message on his Twitter page saying: “In answer to some journos. Am thrilled my daughter now has a brother. Adore them both to an uncool degree. They have a fab mum.”

Hugh Grant, 52, tweeted again at 6.44 p.m: “And to be crystal clear. I am the Daddy.”

The star is on the certificate as the child’s father under his full name Hugh John Mungo Grant with his occupation listed as “actor”.

Tinglan Hong, 32, who lives at a mansion in Fulham, West London, bought for her by Hugh Grant last year, lists her occupation as “housewife”.

Tinglan Hong and Hugh Grant have welcomed their second child together, a baby boy named Felix Chang

Felix Chang’s birth was registered at Westminster Register Office five days later than is technically permitted by Westminster City Council rules. These state that parents should register their children within 42 days of their baby’s arrival.

According to the certificate, the birth was registered by “the signature of Tinglan Hong [and a] statutory declaration made by Hugh John Mungo Grant on January 17”.

A statutory declaration of acknowledgement of parentage, which must be made in front of a magistrate, Justice of the Peace or solicitor, can be used to register a birth if the child’s parents are unmarried and one parent is unable to attend the registration.

Felix Chang’s arrival comes almost 17 months after Tinglan Hong gave birth to the couple’s first child, daughter Tabitha Xaio Xi Hong Grant, at London’s Portland Hospital.

Tinglan Hong, who was born in Zhejiang province in eastern China and moved to Britain in 2003, is understood to have met Hugh Grant in a Chelsea wine bar 2008.

Hugh Grant and Tinglan Hong struck up an unlikely friendship before embarking on a relationship in January 2011.

Tabitha’s arrival was kept secret for two months until Hugh Grant’s spokesman released a statement confirming the birth but adding that the actor was no longer in a relationship with Tinglan Hong.