You’ll see that singer Bell Nuntita easily wins over the crowd with her rendition of a typically sappy Thai pop tune. Then, to the crowd’s amazement, she suddenly switches up her pipes and begins singing like a dude. (The switch-up happens at the 1:04 mark.)
It seems Bell was born male but has transitioned into an extremely convincing female. The odd dissonance of hearing Bell croon like a guy gets squeals from the audience. By the song’s end, they’re going nuts.