Comedian Volodymyr Zelensky steps into his new role as Ukrainian president with his inauguration on Monday, launching a new era for the country wracked by war and economic difficulties.
A month after scoring a landslide victory against incumbent Petro Poroshenko in polls, the 41-year-old becomes Ukraine's youngest post-Soviet president.
He will swear an oath in a ceremony starting at 0700 GMT. According to tradition, he will place his hand on a copy of the constitution and possibly also a Bible.
He will then give an address to the nation that will be closely watched for clues on his future course.
So far little is known about his precise policies after a campaign that capitalised on public disillusionment with the political establishment and promised to "break the system".
Uniquely for a first-time president, Zelensky has played the scene before -- for laughs. He starred as a history teacher who was unexpectedly elected president in the comedy series "Servant of the People".
Just a few months ago, the idea that Zelensky would be inaugurated for real seemed equally unlikely.
When the actor and comedian announced his candidacy on December 31, few took it seriously, but after an unprecedented campaign largely waged through social media, he won more than 73 percent in the second round on April 21, trouncing Poroshenko.
Poroshenko led Ukraine for five years, overseeing the fallout over Russia's annexation of Crimea and armed conflict with Moscow-backed separatists in the country's East that has caused some 13,000 deaths.
Poroshenko averted complete collapse and launched a series of key reforms but was widely criticised for failing to improve Ukrainians' living standards or effectively fight all-pervasive corruption.
Country needs changes
Zelensky has vowed to continue the country's pro-Western course but beyond that his programme is still sketchy and his team largely unknown. His critics question how he will deal with the enormous challenges of the separatist conflict and ongoing economic problems.
The leader of one of the self-proclaimed separatist republics in Ukraine's industrial Donbass region, Denis Pushilin, on Friday told Russia's RIA Novosti news agency that he was "ready for dialogue" with the new authorities in Kiev, "naturally taking into account the interests of Donbass".
Nevertheless he condemned what he called "destructive" statements by Zelensky's team and accused Kiev of "blocking the peace process" which has long stalled.
Also under question is whether Zelensky will be able to govern without a parliamentary majority.
Even setting a date for his inauguration took weeks of negotiations, with Zelensky exasperatedly calling lawmakers "petty crooks".
Zelensky has threatened to dissolve the parliament and hold snap elections before the set date in October to benefit from his current popularity. But lawmakers are determined to thwart his efforts in launching the complex process.
"The country needs changes and fundamental reforms," the president-elect's team said in a statement on Friday.
"This is the demand of the Ukrainian people. And for that, we need a parliament that functions."
Ukraine's allies have given Zelensky a warm welcome, but one Ukrainian site specialising in international affairs, Evropeyska Pravda, suggested this was a "hug strategy" to ensure he continued to pursue a rapprochement with the West.
The new president will immediately have to deal with a number of sensitive international issues, giving him a foretaste of the challenges lying ahead.
Three days after Zelensky's election, the Kremlin announced it was easing procedures for those living in the eastern separatist regions to gain Russian citizenship. Many observers in Kiev saw this as Moscow issuing a challenge to Zelensky and he strongly condemned the move.
In a sign of possible tensions between Kiev and Washington, Ukraine's key ally against Moscow, US President Donald Trump's personal lawyer Rudy Giuliani this month cancelled a visit to Kiev, saying Zelensky is "surrounded by people who are enemies of the (US) president."
The febrile political situation prompted one pro-Western lawmaker, Serguiy Vysotsky, to warn Zelensky that the inauguration "isn't the end of your adventures -- it's just the beginning"