Casey Ranger, 30, shared a lengthy Instagram post claiming that Jack, 29, has spoken ‘in a deceiving way’ about being a father on the show.
She wrote: ‘The older I get the more I realise the important of protecting my own inner peace, I started to realise the beauty of not reacting to certain people & certain situations.
‘In the last week I’ve also realised that keeping certain things so close to my chest isn’t always the best thing to do and that suppressing certain emotions to “keep the peace” will only have a negative impact on my own emotional well being.
‘After keeping quiet for so long I now feel like I’m being backed into a corner and have no option but to speak up for the sake of my little girl & my own peace of mind.’
Casey added: ‘It was extremely difficult to watch Jack speak about Blossom on the TV show earlier this week, he spoke in such a deceiving way that tried to present himself to the nation as a “father”.
‘A father who hasn’t gone out of way once to buy his daughter a teddy bear.
‘Any one who watched it may have been fooled, but the truth is, he’s seen Blossom three times in eight months!!!!’
Jack had spoken to fellow Islanders Laura Anderson and Dr Alex George on the show about how his life had changed since becoming a dad, and kissed a photo of Blossom on his phone screen during the chat.
Casey continued: ‘The image shown on his phone (that he kissed on the show) was a photo I’d sent to his mum a couple of months ago.
‘Also, his “gratitude rock” shown on his story is a rock my sister helped my niece paint for Blossom during lockdown (this must have been left at his Mum’s in June when he last saw Blossom as it was in her baby bag).
‘It angers me how someone in the public eye can easily twist & manipulate a situation, especially one that involves my daughter.
‘I will not tolerate Jack using Blossom’s name to try and rebuild his public profile as a “dad” and I think it’s only right to speak the truth he puts on such a deceiving act.
‘An insider has also said in the paper this week that “he’s also a father so any girlfriend he welcomes into his life needs to be understanding of this”.
‘This is complete & utter nonsense as the last time he was Blossom was in June so I’m not quite sure where this false information has come from.
‘Don’t be fooled by what you see. I’ve kept quiet for far too long and had to sit back and watch this person use my daughter for his own self gratification.
‘I hope you can understand how difficult it’s been to write this and to speak publicly about such a private matter involving my daughter.’
Jack had also shared a video of his mum with Blossom on his Instagram story on Tuesday night, with the time stamp showing it had been taken in June.
He added another video of him feeding Blossom her first taste of Kinder chocolate, though it is unclear when that video was taken.
Jack had announced the surprise news he had welcomed a child in January, after he and Casey had kept the pregnancy under wraps, telling fans it was ‘undoubtedly the best thing that has ever happened to me’.
The reality star and boxer, who won Love Island with Dani Dyer, has also shared several photos of his daughter on Instagram since she was born.
Although Jack and Casey were not in a romantic relationship when their child was born, the pair had been friends for 10 years.
Metro.co.uk has reached out to Jack’s reps for comment.
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