Born to a Thai mother and an Irish father, Harnett grew up in Finchley, north London. She attended Arts University College Bournemouth, where she studied for a degree in acting and appeared in student productions of plays such as One Thousand and One Nights
Harnett’s musical influences include The Fugees, Whitney Houston, Lauryn Hill, Michael Jackson, Dizzee Rascal, Tina Turner, and Amy Winehouse. Billboard wrote in 2013 that “Harnett’s rich, soulful voice and range has drawn comparisons to Adele, but her recordings are more experimental and contemporary—a brand of jazz-tinged, melodic electronic pop a bit reminiscent of Jessie Ware or Jhené Aiko.