The Eurovision Song Contest is widely known for its fiendishly complex voting system.

To make things more complicated, the European Broadcasting Union, which produces the competition, has made some tweaks for the 2023 edition.

Ahead of the grand final on Saturday night, here is a refresher.

– Here is how it works:

Viewers from all participating countries will be invited to vote for their favourite songs on the night of the grand final on Saturday May 13.

Fans can vote over the phone, by text or via the Eurovision app.

Each person can vote up to 20 times but voters will be unable to select their own country’s entry.

The public votes make up 50% of the total vote, with the other half determined by a professional jury in each participating country.

After viewers have cast their votes, a national spokesperson from the participating countries will be called in to present the points of their professional jury – which range from the maximum “douze points” (12) to zero.

This year the UK’s representative is comedian and actress Catherine Tate.

After the presentation of the scores from the juries, the public points from all participating countries will be combined, providing one score for each song.

– What has changed this year?

For the first time in the competition’s nearly seven-decade history, people from countries outside the contest will be able to vote online and on the app.

Their votes will be converted into points that will have the same weight as one participating country.

Organisers clarified this week that Russians are effectively barred from voting due to financial sanctions on the country making it impossible for them to pay the voting fee.

Russia was banned from competing last year after its invasion of Ukraine.

Russia’s national broadcasters subsequently suspended their memberships of the EBU in protest, preventing them from taking part in future contests.