Gwyneth Paltrow and Chris Martin's smooth divorce is reportedly starting to turn sour.

The A-list pair announced their separation last March, after ten years of marriage. Their divorce was finalised in April 2015.

They've seemingly remained on great terms, even holidaying together with children Apple and Moses. However things apparently aren't too rosy anymore.

"Things might have seemed too good to be true between Gwyneth and Chris and they did start off well because she felt like she had all of the control. But like any 'smooth' break-up, things started to go wrong as they each got more serious with their new partners," a source told British magazine Grazia.

Chris, 38, has been continually linked to 24-year-old Jennifer Lawrence, who he's thought to have been dating since last summer. Gwyneth, 42, is currently loved up with TV writer and director Brad Falchuk, 44.

It was around the time of Chris and Gwyneth's divorce that their happy separation reportedly started to unravel.

"Around April they started to row more. Chris was spending more time with Jen and apparently responding to Gwyneth's demands less quickly. She seemed to be furious when Chris was pictured going away with Jennifer in April but really I think it was because it was clear he'd started to care for Jen," the source said.

It was also around this time that Chris and Gwyneth stopped having joint therapy, says the insider.

"They were meeting once a week to maintain their divorce goals," the source added.