Tens of thousands of Georgians have rallied in the capital as the ex-Soviet state's richest man launched his bid to oust President Mikheil Saakashvili's governing party at elections in October.
At least 40,000 supporters of billionaire tycoon-cum-opposition leader Bidzina Ivanishvili's Georgian Dream opposition alliance packed into Tbilisi's Freedom Square on Sunday for the lavishly-staged rally.
It was the biggest rally since 2009 by an opposition revitalised by the super-rich businessman's intervention, although opinion polls suggest his alliance trails behind the governing party.
Ivanishvili, Georgia's richest man and leading philanthropist, made his entry into politics last October - announcing that he was forming a political party with the aim of winning the parliamentary vote and assuming the post of prime minister.
"My dream has always been a strong and united Georgia, where people live freely and are paid what they are worth," Ivanishvili said to the crowd. "I waited for Georgia to become strong and united, but the transitional period after the gaining of independence dragged on and I decided to begin to fight this regime."
Saakashvili's second and last presidential term ends in January and his future plans are unclear. He has not excluded becoming prime minister, a position that will gain additional powers under a 2010 constitutional reform that his opponents said was designed to allow Saakashvili to remain a political force after leaving the presidency.
But this would bring unwelcome comparisons to Russian President Vladimir Putin, who spent the past four years as prime minister to accommodate a constitutional ban on two consecutive presidential terms.
'Your time is up'
Sunday's rally was opened by Kakha Kaladze, the former captain of Georgia's national football team who played for nine seasons with Milan, and it ended with a performance by Ivanishvili's eldest son, Bera, a rap musician.
Kaladze, who recently retired from playing in Italy's Serie A, told the crowd that Saakashvili must quit.
"Misha [Saakashvili], your time is up. Go!" Kaladze said.
Before the rally, columns of Ivanishvili supporters had marched through the city.
"We need real democracy, real freedom, not Saakashvili's fairy tales," said one participant, unemployed Juliet Tsulaia.
Georgia won its independence with the collapse of the Soviet Union in 1991 and began moving closer to the West when Saakashvili became president in January 2004.
He is credited with pushing through a series of political and economic reforms, but he also led the country into a brief but disastrous war with Russia in 2008 over two breakaway Georgian republics now fully allied with Moscow and beyond Tbilisi's control.
Saakashvili weathered weeks of opposition demonstrations in 2009 demanding his resignation over his handling of the war, but the splintered opposition groups failed to coordinate and the protests fizzled out.
Ivanishvili has formed a coalition with some opposition parties but has refused to work with others, including the party led by veteran opposition leader Nino Burdzhanadze.
Worth $6.4bn according to Forbes magazine, Ivanishvili was stripped of his Georgian passport for violating citizenship laws after announcing his challenge to Saakashvili last year.
However parliament this month voted to change the constitution to allow EU citizens like Ivanishvili, who holds a French passport, to contest parliamentary polls.
Saakashvili's allies have accused the businessman, who made his fortune in Russia, of being a stooge for Georgia's enemies in Moscow.