"Young people are leading the way and showing the world how we should react to this," Thunberg, 21, said, wrapped in a keffiyeh, the traditional scarf.
Eurovision winner Gali Atari, from 1979's Milk and Honey, reminds Golan to remember
During the performance of Eden Golan's song "Hurricane", spectators in the audience booed in contempt, and some even left the hall.
The singer, whose music has since been banned in her home country, speaks out against war.
Jerusalem-born Tali Golergant, representing Luxembourg in Eurovision, advanced to the finals. Israel's contestant, Eden Golan, will perform in the second semi-final on Thursday.
Israeli Eurovision contestant Eden Golan skipped the song contest's opening gala ceremony on the Turquoise Carpet to instead attend a Holocaust Remembrance Day ceremony with Malmo's Jewish residents.
The announcement comes ahead of an expected influx of travel to Sweden for the beginning of the Eurovision Song Contest on May 7.
Anti-Israel activists have been calling for months to bar Israel from the contest and have unsuccessfully lobbied other countries’ participants to boycott the competition.
Four Jews living in Malmo, Sweden, reflect on the rise in antisemitic and anti-Israel tensions in the city, which have spiked since October 7, ahead of Eurovision.
The international song contest will be held this year in Malmo, Sweden, considered to be one of the most antisemitic cities in the world, making Israel's participation more complicated.