A poet disguised as a songwriter, Holly Humberstone, 21, has been quietly making sophisticated pop for a couple of years and building a solid following, signing this year to major labels Interscope and Polydor and performing live on Jimmy Fallon. This latest song, Scarlett, might be the best of the bunch. Upbeat, driving, with a super catchy chorus, Humberstone weaves in and out of the music like a voyeur. As she told the crowd at a recent UK music festival, she wrote the song about a friend’s breakup. Maybe, but a lot of the action sounds awfully close to home. Her observational skills are what sets her apart from the current crop of confessional female popsters, but what hooks the listener is how she invests herself emotionally in her music. Her voice is not a big one, but it carries far and wide. Big hopes on Humberstone’s slender frame, but something tells me she can handle it.