Clad in leg-hugging pants and a jacket studded with glittering hearts, Thai Princess Ubolratana Rajakanya performs a cheeky luk thung number that leaves her audience gyrating downstage. The crowd, already stoked by the country music, squeals when she starts flinging stalks of roses into the air.

"It's Valentine's Day today. Let's love each other, okay?" she tells the teenagers massed at a school in Phichit province, some 300km north of Bangkok, for a concert held as part of her anti-drug campaign. "I'm happy to come see you all in person. Seeing (each other) from television may not be good enough."