Lee Hsien Loong, the son of Singapore's founding father, has been sworn in as the island-state's new prime minister.
Mr Lee has been deputy PM since 1990
Mr Lee, son of Lee Kuan Yew, has long been seen as a successor to the outgoing prime minister, Goh Chok Tong.
Mr Lee entered politics more than 20 years ago and has held many senior positions, including deputy leader.
About 1,400 people from all walks of life were invited to the official ceremony, which was held on the lawn of the Istana presidential residence.
The new prime minister was sworn in by Chief Justice Yong Pung How in a televised event on Thursday evening.
The succession process - like so much else in Singapore - had been carefully controlled and co-ordinated.
Singapore's leadership transition got under way on Tuesday, when Mr Goh officially resigned.
"Planned, orderly transition is what distinguishes Singapore," Mr Goh said in his televised farewell address.
His departure leaves room for Mr Lee, who has often been criticised as aloof and rather humourless, to finally step out of his father's shadow.
Some analysts are hoping he might usher in a new era of openness, and he has previously spoken of the need for Singapore to shake off its reputation as an over-protective, nanny state.
The broad guest list for Thursday's ceremony was drawn up at the Mr Lee's request "to be as inclusive as possible," The Straits Times reported.
But correspondents say that, like his father, Mr Lee appears to be socially conservative.
His chosen cabinet contains few new faces, with most of the changes being job swaps between existing ministers.