Zayn Malik and Louis Tomlinson are fighting on Twitter

Out of all the difficult moments to come out of Zayn leaving One Direction, this has got to be one of the worst. 

Zayn Malik and Louis Tomlinson seem to be taking swipes at each other on Twitter.

Earlier today, Naughty Boy posted an edited snap of himself and Zayn, along with the caption "Replace this." 

This angered One Direction's huge following as fans believed this was a dig at the band. 

Louis then put up a, erm, not so subtle tweet in response to Naughty Boy's snap. 

He said: “Remember when you were 12 and you used to think those Mac filters for your pictures were cool haha ! Some people still do HA!”

If this wasn't heartbreaking enough to hear, Zayn then tweeted: "@Louis_Tomlinson remember when you had a life and stopped making bitchy comments about mine?"

Naught Boy then retweeted Zayn's tweet, eeeek…

How can we be expected to take sides here, it's just not possible…

Fans are now angry at Zayn and many have lost respect for him for saying that to Louis when they spent five years in One Direction together.

Oh dear…

Zayn left One Direction this year to live a normal life but has been spending a lot of time with producer, Naughty Boy. He is set to wed Perrie Edwards this summer after rumours surfaced about him cheating on her while on tour.