Mamma Mia! is based on the songs of ABBA, a Swedish pop/dance group active from 1972 to 1982 and one of the most popular international pop groups of all time, repeatedly topping the charts in Europe, North and South America and Australia. Following the premiere of the musical in London in 1999, ABBA Gold topped the charts in the United Kingdom again. Producer Judy Craymer met songwriters Björn Ulvaeus and Benny Andersson in 1983 when .they were working with Tim Rice on Chess.[3] It was the song "The Winner Takes It All" that suggested to her the theatrical potential of their pop songs.[3] Though unenthusiastic, the duo were not completely opposed to the idea.