Cheryl Tweedy and Liam Payne have said they are "going our separate ways" in nearly-identical posts to their 40 million Twitter followers.
The former Girls Aloud star, 35, and One Direction member, 24, have decided to split after a two-year relationship - and just over a year since their one-year-old son called Bear was born.
They told their followers that separating had been "a tough decision for us to make".
"We still have so much love for each other as a family," they said.
"Bear is our world and we ask that you respect his privacy as we navigate our way through this together."
Tweedy was previously married to footballer Ashley Cole for four years before their divorce in 2010.
Four years later she married Jean-Bernard Versini in a secret beach wedding, but by the following year they had split.
She and Payne had been in a relationship since December 2015.
They met on The X Factor in 2008, when she was a judge and he auditioned as a solo contestant, then 14 years old.
In February, the pair put on a public display of unity at the Brit Awards amid speculation over their relationship.
Tweedy later hit back at reports that their appearance had been a "stunt", saying the suggestion was "just ludicrous and a bit weird".
In March, Tweedy responded to images of her partner and another woman, saying she was an "innocent dancer colleague of Liam's who has a fiance".
She described speculation over the images as a "desperate attempt to try to cause problems between Liam and I".
The decision to split up was made two weeks ago, according to The Sun, and Payne has moved out of the Surrey mansion they shared.