Zayn Malik appears to fall out with producer Naughty Boy on Twitter

Former One Direction star Zayn Malik seems to have fallen out with collaborator Naughty Boy.

He's called him "a fat joke" in a series of tweets.

The singer, who quit the boy band earlier this year, spent time in the studio with Naughty Boy working on material.

The producer, whose real name is Shahid Khan, put a track online featuring Malik singing

A tweet from Malik's account now reads: "You fat joke stop pretending we're friends no one knows you."
A tweet from Malik's account now reads: "You fat joke stop pretending we're friends no one knows you."
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In another tweet that seems to refer to Naughty Boy, Malik said: "Someone learned how to upload a video... maybe now he should learn how to use logic ha you ain't [nothing] but a faker."

#ZAYNHASNOCHILL has been trending on Twitter all day with fans asking whether Malik's account has been hacked.

Newsbeat has asked the singer's management to comment on the tweets.