Shirley Bassey is the most successful female British chart artist of all time and the first Welsh artist to reach No 1 in the charts. They Sold a Million: Shirley Bassey celebrates Wales's greatest diva in her 60th year in showbusiness. The film focuses on her early break through the years from her upbringing in Cardiff's Tiger Bay and Splott, her performances in clubs and theatre in the mid-50s, through to her first chart successes and the recording of Goldfinger. The documentary features interviews with her friends and contemporaries such as the great Welsh comedian Wyn Calvin, dancer Louise Freeman, Goldfinger lyricist Leslie Bricusse, as well as previous interviews with Shirley. The film explores the ingredients which made Shirley Bassey a unique international phenomenon which has endured and recalls some of her greatest performances, such as Glastonbury in 2007.