Speaking to Reveal, Max had said that the weeks he spent with Jess after they returned home from Majorca were the "worst of his life". He went on to slam his co-star for being "possessive" and "argumentative" and clearly hitting a nerve, Jess couldn't resist having her say.
Calling out Max for her comments, the starlet tweeted us directly saying: "Biggest load of bullsh*t I've ever read in my life, he went out every night and I didn't give a f***, can't face facts he's a cheat."
Insisting she was done with Max and their failed romance, Jess then added: "Lols like why's he mentioning my name still, moved on boring me now, more like he made my 3 weeks hell on earth."
Jess' comments come after we caught up with Max at a showbiz party last night and he didn't hold back when conversation turned to his former flame.
Explaining why the pair had split, he claims: "[Jess] wasn't the same person in the outside world and that's why it didn't work out.
"Jess is vile and nasty. The three weeks after I left the show were the worst of my life. She was possessive and argumentative, just an absolute nightmare."
Following their break up, Max was subject to plenty of criticism on social media, especially after he was seen kissing Charlotte Crosby shortly after.
Insisting the negative comments he has been receiving are uncalled for, the reality star added: "I got a lot of hate for breaking up with Jess, but this was the reason. It wasn't because I wanted to get with other girls, it was because we just didn't get on. It's hurtful because I still get hate from it now."
Jess and Max first got together back in July while starring on ITV2's dating show Love Island. Despite going on to win the show, things didn't work out for the pair and their romance soon hit a rocky patch when Jess and Max returned home.
After much speculation about their relationship, Jess and Max finally confirmed in August they had split - just six weeks after becoming an official item.
At the time it had seen amicable, with Max telling fans the pair had given it their "best shot" and Jess stating some things are just not meant to be.
However, after pictures emerged of Max and Charlotte together (they are now officially dating), Jess was quick to hit out at her ex-beau for disrespecting her.
Branding him "fame hungry" and "desperate" she said: "Didn't expect anything less, compulsive liar and fame hungry little boy. Laughable. Only two days ago [he] was telling me he missed me!"
Jess then later accused Max of rubbing his new romance with Charlotte in her face when the pair came face-to-face at an awards ceremony, earlier this month.
"Tonight was the first time I've seen him and it got too much," she explained. "I don't have feelings for him anymore, but when someone you've been with comes up to you and rubs his new relationship in your face, it's going to hurt."
"He told me how well it's going with Charlotte and that he has already met her parents," she added. "He's just a d***, a total player and doesn't care about anyone."
It's pretty clear there's no love lost between the pair.
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