Jesy Nelson has thanked fans as she explained her decision to leave Little Mix, saying "recently being in the band has really taken a toll on my mental health".
Nelson (29) is stepping away from the group after nine years and said in an Instagram post it had been "the most incredible time of my life".
Band members Jade Thirlwall, Leigh-Anne Pinnock and Perrie Edwards also announced the news in a string of tweets.
Nelson's Instagram post said: "To all my Mixers, The past nine years in Little Mix has been the most incredible time of my life.
"We have achieved things I never thought possible. From winning our first Brit Award to our sold out shows at the 02.
"Making friends and fans all over the world I can't thank you all enough from the bottom of my heart for making me feel like the luckiest girl in the world.
"You have always been there to support and encourage me and I will never ever forget it.
"The truth is recently being in the band has really taken a toll on my mental health.
"I find the constant pressure of being in a girl group and living up to expectations very hard.
"There comes a time in life when we need to reinvest in taking care of ourselves rather than focussing on making other people happy, and I feel like now is the time to begin that process."