A short history of JoJo: She released her self-titled debut in 2004 when she was 13 and scored a Top 20 hit with the Kidz Bop-perfect anthem "Leave (Get Out)." In 2006, she released her follow-up, The High Road, which contained the Top 5 hit "Too Little Too Late." Along the way, she has suffered record-company bullshit and picked up a legion of stans. Last year, she released "a riff on Drake's "Marvin's Room," in which she said "fuck." Maturation had set in.

JoJo's "Marvin's" grabbed the attention of Drake's not-so-secret weapon, the atmosphere-obsessed producer Noah "40" Shebib. JoJo's new single, the first off her forthcoming Jumping Trains album, is the result of her collaboration with 40. I have mostly ignored this girl, figuring she couldn't possibly have ditched the cheese of her teeny-bopping youth. I can ignore her no longer. "Demonstrate" is a monster, thanks as much to 40's production (the backwards effect in the hook! the way it yields to an even hookier hook, tension-and-release style!) as JoJo's confidently understated vocal. Don't be surprised when this one blows up. Being grown sounds great on this girl.