The London-based singer’s first U.S. single, ”Down” (currently at No. 2 on Billboard‘s Hot 100), is a surprise dance-pop smash. ”It’s nuts!” he says. Jay Sean was already a major star across the pond when Lil Wayne became obsessed with a clip of his on YouTube and helped get him signed to Cash Money Records. ”The first time we met,” Jay Sean recalls, ”he said, ‘Yo, man, I love your vibe. Don’t change.”’ He’s big in India, too, thanks in part to a cameo in the 2005 Bollywood film Kyaa Kool Hai Hum. ”Luckily, I starred as myself,” he laughs.