Justin Bieber 'accuses Selena of cheating with Zayn'
Justin then reportedly accused Selena of cheating on him with former One Direction star Zayn Malik.
He wrote: "I cheated...Oh and I forgot about you and Zayn (sic)."
Selena previously admitted she would love to date Zayn, who is currently in a relationship with Gigi Hadid.
She said: "If he had asked me out on a date, I would be seen with him. Just kidding, but not kidding."
However, she then hit back and accused Justin of cheating her throughout their on/off relationship which ended in 2014.
She wrote: "Funny how the ones that cheated multiple times, are pointing the finger at the ones that were forgiving and supportive, no wonder fans are mad. Sad. All love (sic)."