Isabelle entered the house half way through this year's series to surprise Kieran.
While in Ibiza last year she hooked up with Kieran, we were told. Speaking before entering the villa, she said they really hit it off and she’ll be insulted if he doesn’t remember her.
According to former housemate Lotan, who was ejected from the house after a row with Isabelle, the pair's history is more than a holiday fling.
“I chose to bring in someone one of my mates had been with, thinking that would go down well…how wrong was I?” Lotan joked about choosing to bring in Isabelle into the house for Kieran as part of a task.
He teased to the Daily Express about Kieran and Isabelle's past: “There’s more to that story, but it’s not my story to tell.”
“She’s in a very strong position where she’s seen us for weeks,” he went on. “We’ve been in there for weeks. She hasn’t got cabin fever yet so she’s not missing anyone.
“In the first couple of days everyone got on with everyone, she’s not in there to get on with people. "
Lotan explained: “She can destroy things because she’s seen things and heard things that perhaps I don’t want the other housemates to know about me.
“It doesn’t matter if the public know about it, but if someone in the house uses it against me, to come in and abuse her position, if that’s the game - and it is a game - but I didn’t want to be a part of that game.”
After her dramatic entrance - and 'taking out' Lotan - Isabelle is now the favourite to win Big Brother 2017.
The show continues at 8PM tonight on Channel 5.