Jesy quit Little Mix , nine years after the band were first formed on The X Factor.After admitting that her time in the ground has been "the most incredible time" of her life, Jesy admitted that it also "has really taken a toll on my mental health".X Factor: The most shocking contestant transformations - SLIDERLeon JacksonThis spiky-haired teen won X Factor waaaaay back in 2007, scoring a Christmas number one with a cover of Whitney Houston and Mariah Carey's When You Believe.