Taking to the social media site, Stephanie shared a series of tweets directed at Jeremy, after she claims he accused her of not actually being pregnant.
Stephanie accused Jeremy of taking drugs and warned he won't have any involvement with their child.
The former Hollyoaks actress tweeted: "Tell me im not pregnant and keep denying your child, and Ill throw u right under that buss as the s*it I have in u, u would never survive! (sic)"
Steph added: "F**k meover when im pregnant with YOUR child while u do drugs.Ill f**k uover twice as bad my dear u will have nothing to do with your baby!"
There is no evidence to support Stephanie's claims surrounding drug use. When contacted by Reveal, a rep for Jeremy for had no comment to make.
Steph's outbust appears to have stemmed from messages she and Jeremy had exchanged earlier. Stephanie shared screenshots online and in the texts, a sender who she claims to be Jeremy accuses her of being an escort.
Stephanie hit back: "An escort now... wow. I'm blocking and deleting this number for good... I'm done with trying, done hearing your lies and accusations and done fighting for you when all you do is lie and accuse... Goodbye Jeremy."
In another exchange, Jeremy appears to confirm he has been on dates with another girl since splitting with Stephanie.
Stephanie's tweets (that have now been deleted) come after she had told followers she "feels sorry" for Jeremy. She accused Jeremy of "not turning up to scans" for their baby, and claimed he has been causing her stress.
Stephanie recently paid a visit to hospital and concerned fans by sharing a photo of an IV drip. She has since assured fans she and her baby are doing ok.
Jeremy, meanwhile, has taken to Twitter himself to have his say.
He posted a lengthy message and called Stephanie out for having "no shame." It read: "Was gonna stay quiet about the whole thing and just let it come out normally, first of all I'd like to let people know I'm perfectly healthy, mind and body, and have took to the break up privately.
"But when me and my family are affected by what I'd call a person with no shame, she is slandering me and trying to portray me in a certain light for a reason. People can choose to believe it or not, I do not care."
Jeremy then accused Stephanie of seeing her ex-boyfriend Sam Reece "for months" behind his back.
He added: "For months she was seeing Sam behind my back and now in Ibiza together. It will all unfold in time. People don't know what I've put up with in that relationship. I was never perfect, but please don't believe 90 percent of what she says.
"I've messed up, but I'd never be as evil. This will be my last message about her #bookclosed."
Stephanie, however, has denied Jeremy's claims about herself and Sam. She hit back that she is at home in Liverpool, while a rep for Steph had no comment to make with regards to Jeremy's tweet and her Twitter activity of late.
Sam, meanwhile, is currently dating new girlfriend Taylor Ward and hasn't addressed Jeremy's tweet. Reveal has contacted a rep for Sam.
Stephanie and Jeremy's latest fallout comes days after she confirmed she is pregnant with their first child. She revealed her baby news to OK! magazine, and said: "My pregnancy was a shock but I can't wait to be a mum. I hope that Jeremy will want to be a part of this baby's life, but if he decides not to then I am prepared to raise our baby on my own."
Steph had previously claimed she was expecting in a now-deleted Instagram post. At the time, Jeremy had responded by assuring fans he would be "responsible for his actions" if Steph's claims turn out to be true.
Earlier this month, he and Stephanie split for the fourth time. The pair got together after controversially falling for each other on Celebrity Big Brother earlier this year. Stephanie had been dating Sam when she entered the house, but split with him on her exit and later pursued things with Jeremy.
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