Isabella Leong, the 22-year-old "partner" of 43-year-old Hong Kong billionaire Richard Li, gave birth to twins at the end of June, a little more than one year after delivering baby boy Ethan.

Various Hong Kong media reports are saying that Li, son of the "richest man in Asia" Li Ka-shing, put aside work and flew to San Francisco in time for the latest delivery.

A Sina article said Leong kept herself busy during her pregnancy by learning how to cook French cuisine for her extended family.