Netiporn "Bung" Sanesangkhom, 28, had been accused of insulting Thailand's monarchy.

The protesters were part of youth-led pro-democracy rallies in 2020 calling for royal reforms.

The three finger gesture has become a defining symbol of demonstrations in Myanmar and Thailand.

The sentence is the country's harshest ever for insulting the monarchy.

Thai group Rap Against Dictatorship is known for its outspoken comments against the military and monarchy,