Najib Razak has been sworn in as Malaysia's sixth Prime Minister.
In a brief ceremony at the National Palace in Kuala Lumpur, Mr Najib swore an oath to protect the constitution of Malaysia.
King Mizan Zainal Abidin presided over the official ceremony which was televised live across the country.
Mr Najib became a member of parliament at the age of 23 after the death of his father, Abdul Razak, who led Malaysia from 1970 to 1976.
His uncle was also a prime minister.
There has been a mixed reaction to the 55-year-old's rise to power.
Political activists worry that he will clamp down on freedom of speech and protest groups.
And Mr Najib continues to face scrutiny over the death of the girlfriend of one of his key aides.
But some analysts believe he will be able to address the failing economy and the ethnic tensions in the country.