Caroline is said to have dumped the music manager after 'rekindling' their romance in June.
Love Island presenter Caroline reportedly hinted at the break up in a series of now-deleted tweets on Thursday night (13 August).
According to The Sun, the 35-year-old went on a Twitter rant, allegedly saying: "@jackb_street dear you. Tiny little man. You'll never change for anyone. But good luck with that."
She reportedly said in a following tweet: "Honestly he is evil."
Caroline and Jack - who manages Sam Smith - were previously together for around 18 months.
They split in December 2014 while Caroline was taking part in Strictly Come Dancing (which she later went on to win) amid unconfirmed reports that he had grown close to Glee star Dianna Agron.
Caroline and Jack got back together in June after they were spotted together at Glastonbury festival.
Reveal have contacted Caroline's rep for comment.
Last night, Caroline didn't reference any split speculation but simply said: "Ibiza bound!!!! See ya in a bit."
Try Reveal's digital edition on iPhone & iPad. Subscribe now & never miss an issue!