The 36 year old took to Twitter to reveal the sad news, three years after the pair welcomed their son Daye.
Hollyoaks star Jennifer wrote to her 363,000 followers: "Greg and I decided to part ways amicably a couple months ago.
The post has been liked more than 32,000 on the social media platform while Jennifer has ensured comments are disabled.
"We remain friends and we both will continue to happily co parent Daye and would appreciate privacy during these times.
"Thank you to everyone who has supported us before, during and after this."
They for almost eight years after meeting in 2012 after Greg, 35, quit the MTV reality show after just one series.
Jennifer and Greg had a long-distance relationship for five years. While Greg lived in Newcastle, she lived in Liverpool for Hollyoaks filming commitments. The pair then moved in together in 2017, the same year she gave birth to their son Daye.
Speaking to OK! magazine back in 2017, the couple said they would want to have two children together.
At the time, Greg said: "I think I'd like to have two kids. A boy and girl would be nice. I've got two nephews and I love spending time with them."
Jennifer previously admitted in 2018 that she thought Greg had proposed to her, though that wasn't the case.
"I thought Greg had proposed to me on my birthday," she told Loose Women. "He got a ring out, I'd just got back from work. I was too tired for it. I said 'can we please do this another time, I'm tired'.
"It was just a ring 'for us' though, not an engagement one."
The actress said the couple split "amicably" a few months ago
The actress is best known for playing Mercedes McQueen on hit soap Hollyoaks.