The son of Pakistan's former prime minister Benazir Bhutto has launched his political career, vowing to continue her legacy.
Speaking in front of more than 200,000 supporters at the family mausoleum, 24-year-old Bilawal Bhutto Zardari said: "I am the heir to the martyr."
He was referring to his mother, assassinated exactly five years ago, and grandfather Zulfikar Ali Bhutto, the founder of the current ruling party who was hanged by a former military ruler.
In his first address to a mass rally televised live, Mr Bhutto, who was educated at Oxford University, said: "If you kill one Bhutto, there will be a Bhutto in every house."
He added: "Bhutto is not a name, it is an obsession, a passion, a love. You can chain our feet to the ground but we will still keep moving."
At the mausoleum in Garhi Khuda Bakhsh in the southern province of Sindh, he was joined by hundreds of high-ranking officials, including the current president, his father Asif Zardari, to commemorate his mother's killing in a gun and suicide attack during a political campaign rally.
Mr Bhutto was named chairman of the Pakistan People's Party after his mother's death in 2007, but his father was named co-chair due to his youth.
He has mainly played a background role until now while he completed his studies in Britain.
He is still not old enough to contest the elections scheduled for spring - the minimum age is 25 - but he is likely to be a key asset for his party and could act as a figurehead for the campaign.
The party's popularity has plummeted since it took power nearly five years ago as the country has struggled with a weak economy and a bloody Taliban insurgency.
Mr Bhutto, who turns 25 in September, criticised the judiciary, which has clashed with the current government, by asking why people arrested for suspected involvement in his mother's murder have yet to be convicted.
But some critics have questioned why Mr Zardari has not done more to push forward the investigation during more than four years as president.
Prime Minister Raja Pervez Ashraf told followers waving the party's green, black and red flag that Mr Bhutto "will prove to be an important turning point for democracy and politics".
Rasul Bakhsh Rais, a political science professor at Lahore University of Management Sciences, said it was not a surprise that the party unveiled Bilawal Bhutto Zardari in an attempt to boost its fortunes in the upcoming elections, which are expected by June at the latest.
"This is Pakistan and dynastic politics is the norm," said Mr Rais. "Bilawal is perhaps the only card left in the chest of the Pakistan People's Party."
Benazir Bhutto twice served as prime minister in the 1980s and 1990s but never completed a full term.
Her governments were dismissed both times under the cloud of corruption allegations by presidents who were close to the country's powerful army.
She was killed in an attack on December 27, 2007, shortly after returning from self-imposed exile to participate in national elections.