From the get go, Gaz has pretty much had his sights set on Olivia. He took a backseat when his ex-girlfriend Lillie Lexie Gregg arrived at the villa, but after clearing the air with her over their split, Gaz soon turned his attentions back to Olivia.
So much so, that the pair finally ended up having sex... but only for Gaz to pie Olivia the very next day.
Gaz was sent down to the beach with Olivia and Ashely Cain to greet the latest ex and revealed he was "buzzing" to see it was his former flame from Australia, Chrysten.
Explaining how the pair knew each other, he said: "Every time I end up going to Australia, we always end up getting together. With me and Chrysten it's like a sexual thing. Every time I see her, I just want to f**k her."
Naturally, Olivia wanted to know if she would be competition and asked Chrysten what she was after: meeting someone new or picking up where she left off with Gaz?
Chrysten replied: "I want to see where I stand with Gaz," prompting him to tell her: "I'll happily just crack on with you, me."
Did he forgot Olivia was sitting there in front of him?!
To the camera, Olivia vented: "Gary has been with me pretty much every night in this villa, we slept together last night... what the f**k are you doing with your hands all over her?"
Ash then picked up on the opportunity to tell Chrysten that Gaz and Olivia had a bit of a thing going on, but she insisted she wasn't bothered that the duo had slept together as it happened before she had arrived.
She was then sent on a date with Ash, leaving Gaz and Olivia to tell the others who their latest addition was.
While Gary explained it was Chrysten, Olivia told him: "I feel like you totally mugged me off then by the way."
He sweepingly apologised before continuing to talk about Chrysten, leaving Olivia to declare that she was done with him. She said in private: "That boy has totally f**ked it with me. I can't believe he dismissed me like I wasn't even there."
Kayleigh Morris then asked whether Chrysten was good-looking and Olivia replied: "She's quite fake looking."
Kayleigh remarked: "Olivia is shocked to be pied by Gaz. Do you not know his reputation?"
Meanwhile, on their date, Chrysten revealed to Ash that Gaz had cheated on Lillie with her during a trip to Oz.
She explained: "I met Gaz March 2015, we were both blind drunk. I ended up letting him up to my room and we had sex. Then he said, 'Hold on a second, I've got to take a phone call.' And it was Lillie."
"I don't want to be the one to tell Lillie, I personally think Gaz should do it as he was the one who cheated," Chrsyten claimed. "It's not my fault."
Gary, however, had planned on denying it. When quizzed by Lillie over Chrysten, he insisted he had never cheated but was later left looking sheepish when Chrysten revealed they had.
Lillie broke down in tears and branded Gaz a "horrible person."
Choking on her words, she said: "Don't take someone's kindness for weakness. Don't take advantage of someone when they trust you... Sh*t."
Ex On The Beach continues Tuesday 27 September at 10pm on MTV.
Follow us on Twitter @RevealMag for all your celeb, fashion and beauty news!
Fancy winning some GREAT prizes? Check out Reveal Competitions here!