Read this: While most artists became established in other formats before moving to adult contemporary, Michael Bublé and Josh Groban started out as AC artists. Throughout this decade, artists such as Nick Lachey, James Blunt, John Mayer, Bruno Mars, Jason Mraz, Kelly Clarkson, Adele, Clay Aiken and Susan Boyle have become successful thanks to a ballad heavy sound. Much as some hot AC and modern rock artists have crossed over into each other, so too has soft AC crossed with country music in this decade. Country musicians such as Faith Hill, Shania Twain, LeAnn Rimes and Carrie Underwood have had success on both charts.
Now answer this question, if there is an answer (If it cannot be answered, return "unanswerable"): Along with Josh Groban, what notable pop artist started out his career on adult contemporary radio?
Michael Bublé