Next week, Lillie will be seen reuniting with Gary - aka Gaz - in the new series of Ex On The Beach and, ahead of its launch, she has been spilling the beans.
In a short clip posted by MTV on Instagram, Lillie has revealed that Gaz shared a video of himself "snogging" an 18-year-old girl within hours of their split. Ouch!
Lillie said: "The worst thing I've seen my ex post on social media is probably, the day after we broke up, on his YouTube channel, a video of him snogging an 18-year-old girl at a pool party in Australia."
Last night, Lillie's current boyfriend Stephen Bear dumped her during the latest instalment of Celebrity Big Brother and was later heard getting up to no good with fellow housemate Chloe Khan in the toilet.
Making reference to this, one fan responded to MTV's video of Lillie by saying: "Obviously this was filmed before last night's CBB? To me that's the worst ever #disgusting."
Meanwhile, earlier today (9 August) we revealed how Gaz breaks down in tears as he reunites with Lillie in next week's episode of EOTB.
The former couple dated for more than a year before splitting in November 2015 and Gaz previously revealed that his sole intention for going back on the MTV show was to get closure from his ex.
"My reason for going back on Ex On The Beach is probably to sort things out with Lillie," he said. "We didn't really have a closure and we didn't really have a chance to speak.
"It will be nice to see her again, actually get closure and then move on to the next chapter in our lives."
EOTB returns to MTV on Tuesday 16 August at 10pm.
Ex On The Beach 5 | Ep #1 Extended Preview: Part Three
Watch More: www.mtv.co.uk/ex-on-the-beach
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