Justin Bieber. Picture: Instagram

Justin Bieber and Selena Gomez are reportedly having couples therapy after a row over Hailey Baldwin.

The 'Believe' hitmaker has been trying to make amends with people he's upset as part of his renewed Christian faith, and so approached his former girlfriend - who he briefly dated and ended on bad terms with last year - to apologise.

But as part of his new "open and honest" approach to life, the 'Sorry' singer then told Selena about being in contact with Hailey, and she wasn't very happy, TMZ reports.

As a result, the couple agreed to give Christian couples therapy a try and have been attending sessions for a week.

Justin, 23, and Selena, 25, rekindled their relationship a month ago - just weeks after she split from her boyfriend The Weeknd - and are planning to celebrate New Year together. 

It's believed the 'What Do You Mean?' singer reached out to Selena when she underwent an emergency kidney transplant over the summer after her organ started to fail as a result of her battle with Lupus. Her serious illness made the 'Never Say Never' singer realise just how much she loved her. 

And the Canadian pop star knows his girlfriend's family aren't thrilled about their renewed romance but he's said to be determined to prove to them he has grown up and is a changed man.

A source said previously: "Justin is aware Selena's family is not thrilled they are hanging out. They think he caused Selena a lot of grief. Justin hopes he can prove to them that he has changed. He has changed a lot in the past few months. He is a very different person. They have a lot to talk about and are having fun catching up."

Justin and Selena dated on and off for four years before calling time on their turbulent relationship for good in 2015.