Tens of thousands packed into Cairo's Tahrir Square on Sunday in the largest celebration the protest hub has witnessed since Hosni Mubarak's ouster, to celebrate their new president-elect, Mohamed Morsi.
As a military helicopter hovered above the huge square, revellers set off fire works and women ululated for what the crowd said was a victory for their "revolution."
"The old regime has gone. This will be good for Egypt and all Egyptians," said one of the crowd, Khaled Abdel Satar as women behind him ululated.
"This is a victory for the Egyptian revolution," said another, lawyer Mohammed Abdel Ghaffar.
His friend Ahmed Shabrawi added: "It's a rebirth for Egypt. Power will transfer to a civilian president."
At a podium, leaders of Mohamed Morsi's Muslim Brotherhood joined with leftist supporters of the Islamist president-elect and cheered on the crowd.
"The revolution will be victorious," Abdel Halim Qandeel, a leftist activist, roared to the crowd.
"One hand," the crowd chanted back.
The 2011 uprising toppled Mubarak and saw the once-banned Brotherhood thrust to the forefront of politics.
An ailing Mubarak has since been sentenced to life in prison over his involvement in the deaths of protesters during the uprising that killed at least 850 people.
In Tahrir, Islamist politician Safwat Hegazi yelled from the podium "Ululate, o martyr's mother."
Cars and microbuses jammed with Morsi's supporters carrying his posters raced to the square.
"This is proof that the revolution has won, not the Brotherhood. Egypt voted for him," Shabrawi said.
Actually, Morsi won 51.73 percent of the vote in a deeply polarising run-off against Ahmed Shafiq, who was briefly Mubarak's premier during the ousted leader's final days in power.
Across the city, passengers in cars and on motor bikes sounded their horns, waved Egyptian flags and chanted "Morsi, Morsi."
His victory marks the first time Islamists have taken the presidency of the Arab World’s most populous nation, but recent moves by the ruling military to consolidate its power have rendered the post toothless.
It is also the first time since Egypt's monarchy was toppled in 1952 that a civilian leads the country.
The capital was tense before the announcement, with the city's notoriously busy streets deserted and shops and schools closed.
Extra troops and police were deployed as military helicopters flew overhead.
The road to parliament was closed to traffic, and security was tightened around vital establishments.
The election, in which more than 50 million voters were eligible to cast their ballot, saw a 51.8 percent turnout.