Jesy Nelson

She explained: "I find the constant pressure of being in a girl group and living up to expectations very hard."

Writing on Instagram, the 29-year-old said being in the band had been "the most incredible time" but it was now time to "embark on a new chapter".

Her former bandmates said it was "an incredibly sad time for all of us but we are fully supportive of Jesy".

The news comes a month after Nelson said she was taking an "extended" break from the pop group for "private medical reasons".

A statement didn't give any further details about the 29-year-old's condition.

It comes after Nelson recently missed the final of the girl group's BBC One talent show, and their hosting of the MTV European Music Awards.

Little Mix's latest album entered the UK chart at number two on Friday.

All six of the studio albums they have released since forming on The X Factor in 2011 have gone into the top five, and they have had four UK number one singles.