Thai Prime Minister Prayuth Chan-ocha casts his ballot at a polling station during a constitutional referendum vote in Bangkok, Thailand August 7, 2016.[Photo/Agencies]

BANGKOK -- National referendum on Thailand's 2016 draft constitution and its additional question begins at 8 a.m. (0100 GMT) Sunday as planned, major figures such as prime minister Prayut Chan-o-cha, former prime minister Yingluck Shinawatra and Abhisit Vejjajiva have already voted until now.

Prayut, current prime minister and leader of the National Council of Peace and Order went to vote with his wife at a polling station in Bangkok at about 9:10 am.

He called for eligible Thais to come to vote to make a difference and decide the future of Thailand at the scene.

He said earlier that he would vote yes to both questions in the ballot.

About 50.5 million Thais are eligible to vote on the 2 questions on their ballots, the first being "Do you accept the 2016 draft of the constitution?", and the second being "In order to reform the country continuously according to the strategy, should the Senate be allowed to join the House of Representatives in the voting process to select a prime minister for the first five-year period after the first National Assembly is formed under this constitution?"

Meechai Ruchupan, chairman of the Constitution Drafting Committee, came out to vote at a polling station in Nonthaburi Province at about 9:15 am.

The current draft constitution is also called the Meechai version by some Thai media.

"Though familiar with (the draft), I still feel excited...I will be satisfied no matter what the outcome will be, and I don't expect anything because I don't want to be disappointed." Said Meechai to media, adding that referendum on constitution is rare and thus calling for eligible people to cherish the chance.