Ukrainian actor Volodymyr Zelenskiy has won the second round of a presidential election against incumbent Petro Poroshenko by a landslide.

According to a national exit poll showed on Sunday, the political newcomer, who dominated the first round of voting three weeks ago, got more than 70% support.

Polls gave Poroshenko, who has been in power since 2014, 25% of the vote. 

If polls are correct, he will be elected for a five-year term. Official results are expected to come later today.

Zelensky challenged incumbent president Petro Poroshenko who has admitted defeat.