The seventeen and a half year old girls had been telephone operators in Limburg, whilst Theunissen, Wetzles and Coumans were in a group called Scum. Wille played in a group called Ricky Rendall and His Centurions until he married Tonny, and created the group Sweet Reaction that eventually became known as Pussycat.
In 1975 they scored a big European hit with the song "Mississippi". However they had to wait a further year for the single to make the British charts when it climbed to Number One in the UK Singles Chart in October 1976. Penned by Werner Theunissen, the septet became the first Dutch act to top the UK Chart. It is estimated that "Mississippi" sold over five million copies worldwide. It was later followed by "Smile" in 1976, and "Hey Joe" in 1978. Others hits were "If You Ever Come to Amsterdam", "Georgie", "Wet Day in September" and "My Broken Souvenirs". A stellar European career followed that ultimately, at its peak, spanned ten years and included some seventeen albums. By 1978 Hans Lutjens had replaced Coumans on drums, as the band continued to release albums and tour, travelling as far afield as South Africa. They made regular appearances on the West German TV Series, Musikladen, in the late 1970s and early 1980s.
But as the 1980s rolled along, the sisters found it increasingly difficult to finance huge tours with so many Musicians, and replaced their backing band with taped music, and thus Pussycat shifted their image one last time. They continued to play and record through the mid 1980s when they finally disbanded.
Tonny, whose own extra curricular activities had commenced back in 1973 with her own single release "For You" (under the alias Sally Lane), proved especially prolific, unleashing a string of albums, of which New Words to an Old Love Song saw her elected Best Female Country Singer of the Year by the Dutch magazine, Country Gazette.