Singapore's Prime Minister Lee Hsien Loong on Sunday congratulated Prince William and Kate Middleton on their newborn princess.

"Congrats to Prince William and Kate on the birth of their daughter! Remember warmly their visit to us in 2012. Happy that they have an SG50 baby!" PM Lee wrote on his Facebook page.

Singapore's President Tony Tan Keng Yam will be sending the couple an SG50 Baby Jubilee Gift, commemorating the princess's birth in the year that Singapore celebrates its 50th birthday, he added.

Britain's Duchess of Cambridge Kate gave birth to a girl baby on Saturday. The royal couple's first son, Prince George, was born in July 2013.