Zayn - who quit the boyband in March - took to Twitter to tell Louis to ‘stop making bitchy comments’ about his friend, producer Naughty Boy on Wednesday.
Zayn Malik and Louis Tomlinson
Things kicked off after Louis decided to mocked Naughty Boy for posting a grainy selfie of himself with Zayn in the studio.
Referring to the picture, Louis wrote: “Remember when you were 12 and you used to think those Mac filters for your pictures were cool! Some people still do HA!”
Naughty Boy responded: “And some people can’t even sing, but who's complaining when there's autotune?.”
In a series of tweets, which have since been deleted, Louis hit back, saying: “How does it feel to be riding on the back of someone else’s career?”
Naughty Boy responded: “Yeah how does it feel? You’ve been doing that for the last five years.”
Louis retaliated: “I think we’ve done all right in terms of sales and I’ve happened to write on most.”
Wow, it really is just like being back at school, isn’t it?
Zayn obviously agreed and told Louis to stop bitching, tweeting: “Remember when you had a life and stopped making bitchy comments about mine?”
And after deleting that particular tweet, Zayn later took to Twitter again to defend himself after coming under fire from angry 1D fans.
"Don't know why I'm being attacked for defending myself , people got it twisted! I love my fans ?! Every single one of you x," he tweeted.
A source told The Sun: “Naughty Boy feels very protective of Zayn because it’s been a hard time.
“Zayn knows it was unnecessary and bitchy of Louis to start all of this.”