Only an R&B artist could begin an interview with straight, shoulder-length hair and end it, less than an hour later, with a wavy mane of such preposterous proportions that a lion with a perm springs to mind. In a room at her record company?s offices on Broadway, the Barbados-born singer Shontelle Layne is being briskly transformed from a fresh-faced 23-year-old into the sort of impossibly flawless Amazonian goddess that only truly exists in pricey pop videos.