Volodymyr Zelensky (R) is poised to take over the Ukrainian Presidency from Petro Poroshenko (L) (AFP)
Ukrainians vote in the second round of an extraordinary election on Sunday with a comedian who plays a president on TV expected to win in a stunning rebuke to the political establishment.
Forty-one-year-old Volodymyr Zelensky's bid to lead the country was initially dismissed as a joke. But opinion polls suggest incumbent President Petro Poroshenko is heading for defeat amid widespread anger over poverty and corruption.
Polls open at 0500 GMT, with exit poll results expected at 1700 GMT and the first preliminary results several hours later.
Zelensky's victory would open a new chapter in the history of a country that has gone through two popular uprisings in two decades and is mired in a five-year conflict with separatists in the east.
Ukraine is dependent on international aid and Russian energy and the next president will have to deal with Russian President Vladimir Putin and the International Monetary Fund.
Poroshenko, 53, has argued Zelensky is a political novice unfit to be a war-time commander-in-chief.
But the consummate showman has tapped into widespread frustration over graft, poverty and a war that has claimed some 13,000 lives.
"There is a hope that a simple man will better understand us and dismantle the system that we have in our country," said Yuliya Lykhota, 29, a Zelensky supporter.
"It is very important to raise our people's spirits."
Others doubted whether Zelensky, best known for playing the president on TV show "Servant of the People", would be able to take on the country's vested interests.
"I do not believe he will last long once he's elected," said Sergiy Fedorets, 62.
"He has no support in parliament. He'll be eaten alive."
'Not a comedy'
A survey by the Rating pollster this week showed Zelensky winning 73 percent of the vote against 27 percent for Poroshenko.
Poroshenko came to power after a bloody 2014 uprising ousted a Kremlin-backed regime, triggering Moscow's annexation of Crimea.
But many in the country of 45 million people feel the promises of the pro-Western revolution have not been fulfilled.
Zelensky has shunned campaign rallies in favour of comedy gigs and used social media to share political messages, including to 3.7 million followers on Instagram.
His brand of outsider politics and unorthodox style has earned him comparisons to Italy's comedian-turned-politician Beppe Grillo and US President Donald Trump.
But questions have been raised over his links to controversial oligarch Igor Kolomoysky, whose TV channel broadcasts the entertainer's shows.
Analysts say Zelensky's political programme is vague at best and it remains unclear who will fill key positions in his government.
On Saturday, Poroshenko made a last-ditch plea to voters, begging Ukrainians to think twice before backing his rival.
"A five-year presidential term is not a comedy that you can easily switch off if it is no longer funny," he said on Facebook.
"Neither is it a horror movie that can be easily stopped."
Poroshenko supporters credit him with rebuilding the army and securing an Orthodox Church independent of Russia.
But in the first round of the election last month he won only half of Zelensky's vote share.
'All eyes on Ukraine'
The West has closely watched the race amid concern a new government might undo years of economic reforms.
US Secretary of State Mike Pompeo called both Zelensky and Poroshenko on the eve of the run-off vote.
Pompeo "reiterated our commitment to working with whomever the Ukrainian people choose to ensure the success of a secure, prosperous, democratic, & free (country)," Washington's special envoy Kurt Volker wrote on Twitter.
William Taylor, a former US ambassador to Ukraine who co-leads a National Democratic Institute delegation of international observers, said the election result would have an impact around the world.
"All eyes are on Ukraine -- an emerging democracy on the front lines of Russian aggression," he said.(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)