The long-time friends - who have enjoyed a secret fling in the past - had words during The Only Way Is Essexmas after differing on something that happened during a recent night out.
Mario claimed Chloe had asked to come back to his shortly after she split from ex Elliott Wright, but Chloe said she'd wanted a whole group to come back and have an after party.
It was very much a case of he said-she said as they argued their points.
The result? Perhaps they shouldn't be friends anymore...
"You know what I think we're better off doing?" said Mario. "It seems like since we've started trying to be friends again it hasn't really worked. I think we would be better off in the New Year separating and not talking anymore."
Chloe replied: "Well we probably won't now you're branding me a liar!"
Viewers of TOWIE will know that earlier this year it emerged Chloe and Mario had enjoyed a secret month-long fling. Their relationship only came out after the romance had ended.
Chloe and Mario decided to remain friends and Chloe moved on to date co-star Elliott Wright. That romance fell apart during the last series of TOWIE but was rekindled on the Christmas special.
On last night's episode, plenty of time was devoted to a big night out where Mario claimed Chloe had asked him again and again to return to his.
He told Chloe she'd been drunk and said the only reason she wasn't admitting it was because she didn't want to get in trouble with Elliott.
Chloe denied this, saying: "I was drunk that night. I'd just found out Elliott had shared a bed with another woman. I confided in you. I remember the conversation... I don't look at you like that no more. I told you that in Ibiza. I wanted to be friends.
"I thought after what happened and everything we went through... we'd remain respectful to each other and now you've said I asked you to come home with me!"
"You did" countered Mario.
"I didn't" said Chloe.
We wonder if they will go through with being not friends... How will this affect Mario's friendship with Chloe's brother Charlie Sims? Will things be awkward when Mario and Chloe bump into each other? So many questions!
TOWIE will return to ITVBe in the New Year.