Naughty Boy has seemingly taken a shot at Zayn Malik, warning him the world owes him nothing.
The music producer was on hand to give Zayn support when he quit pop supergroup One Direction in March, with the pair quickly heading into the studio together.
Things soured last month, with Zayn calling Naughty Boy a "fat joke" on Twitter. He was apparently annoyed a video of him had been linked, although the producer has insisted it was nothing to do with him.
Now Naughty Boy has reignited the feud, writing a message on Twitter which is widely thought to be aimed at newly-single Zayn.
"grow up man. the world owes you nothing. It's like you're engaged to karma. & karma is a b***h (sic)," he wrote.
Predictably, Zayn's fans are not that impressed by the outburst. They have flocked to the social media website to defend their idol, with some suggesting it's actually Naughty Boy who needs to "grow up".
"Instead of bashing on a guy who has more figures than you have fans why don't you work on that non existent career of yours (sic)," one fumed.
Naughty Boy hadn't previously responded to Zayn online, but he did give an interview giving his side of the story. He feels upset that the heartthrob has turned against him, blaming Zayn's new management for the change.
"I can deal with what he said but he knows the hate I’ve had to endure for him is the bit that upset me," he told British newspaper Sun on Sunday.
"Three months ago he was calling me his best friend at the Asian Awards so it’s a bit sad."
It's been a difficult week for Zayn, with the news that he has split from his Little Mix fiancée Perrie Edwards. He is yet to speak publicly on the news, although she has told fans that she is doing OK via a TV interview. It's been claimed that Zayn was the one who called time on the romance, telling Perrie via text message.
"Who does that? She’s devastated, which everyone understands, but is doing her best to focus on work and to put on a brave face in public," a source told The Sun.