Original sentence: (Frankie Sandford had previously worked together in the band S Club 8).The Saturdays are a pop girl group formed in Britain in 2007, comprising Una Healy, Mollie King, Frankie Sandford, and Vanessa White
Edited sentence: The Saturdays are a pop girl group formed in Britain in 2007, comprising Una Healy, Mollie King, Frankie Sandford, Vanessa White and Rochelle Wiseman (both Frankie Sandford and Rochelle Wiseman had previously worked together in the band S Club 8)