With the recent death of Patty Andrews, the last of the Andrews Sisters vocal harmony group has passed.
The Andrews Sisters made their fame in the 1940s performing their close harmonies for World War Two troops in Africa, Europe and the US and starring in wartime films.
By contrast The Pussycat Dolls made their name as a quasi-burlesque act, titilating audiences with suggestive dancing.
While the Andrews Sisters came together as a trio of sisters singing together, girl groups of today are often assembled by record labels and marketing executives.
Gigwise takes a look at the transformation girl groups have undergone in the last 70 or so years.