This will be Katie's third divorce, she was previously married to Peter Andre from 2005 to 2009 and Alex Reid from 2010-2011.
The former couple met through Katie's best friends Gary Cockerill and Phil Turner.
Following their beach wedding they headed to Weston-Super-Mare in March to bless their wedding and welcomed Jett seven months later.
His latest social media posts appeared to suggest all is well between the couple, before Katie hit back.
She also tweeted a string of broken heart emojis as she headed to bed before waking in time to watch the fight.
Mail Online have contacted representatives for both Katie and Kieran.
It came after her interview with The Sun, detailing how she had caught ex stripper Kieran sending intimate emails to their nanny Nikki Brown, came to light. For a year I was basically paying her to f*** my husband.
Now the mother-of-five has hit back at her Kieran in a vitriolic tweet, branding the video 'fake' and reiterating that the marriage is over once and for all. Alongside the clip, Kieran also posted two photos of himself reclining on the sofa as the fight got underway, with Katie appearing to by lying across him while looking on her phone.
Slamming her third husband she wrote: 'My heart is broken , Kieran's video is fake to make it look like I'm not serious! Another shot showed her leaning on her beau's chest while clutching onto a wine glass in one hand, while Katie could be heard shouting to 'see Mayweather' as Kieran filmed Mc Gregor's pre-fight interview.
She admits it had been merely a 'self-defence mechanism' as she suspected he was sleeping around and had wanted to believe that somebody else would 'want her' and stay faithful.
Despite his infidelity, Katie has insisted she wants the couple's divorce to remain on amicable terms 'for the sake of the kids' and hopes to keep things 'civil'.
I was crying, asking, "How could you do this to me again?