Sri Lanka's election commission on Wednesday announced to hold presidential polls in the country on November 16.
Filing of the nomination papers will start from October 7, the National Election Commission said.
Nearly 15.9 million people are eligible to vote, it said.
According to constitutional provisions, the polls must be held one month before the end of the current president's term.
President Maithripala Sirisena's five-year term is scheduled to end on January 8, 2020.
On May 30, speaking to media in New Delhi after attending Prime Minister Narendra Modi's swearing-in ceremony, Sirisena had said that he was yet to decide on seeking another term.
With today's announcement Sirisena would be making his exit as president two months before the expiry of his full term.
Sirisena was elected for a five year-term on January 8, 2015 when he challenged the incumbent Mahinda Rajapaksa. The former strongman had called snap elections two years ahead of the end of his second term.
Sirisena, backed by the then main Opposition United National Party (UNP), became the common Opposition candidate against his former boss Rajapaksa.
Although Sirisena has not so far declared his intention for a re-run, his souring of relationships with the UNP of Prime Minister Ranil Wickremesinghe has indicated that the UNP would be fielding its own candidate.
Sirisena in October last year sacked Wickremesinghe, who elevated him to the presidency, and replaced him with Rajapaksa. The move led to a constitutional impasse, which lasted over 50 days. After the intervention by the Supreme Court, Wickremesinghe was restored as the prime minister.
Meanwhile, the SLPP has announced Gotabaya Rajapaksa as their presidential candidate, while JVP leader Anura Kumara Dissanayake is set to contest the poll on National People's Power movement ticket, according to media reports.
The UNP and the SLFP are yet to announce their presidential candidates.