Scott Disick and Kourtney Kardashian are ''best friends'' after 2015 split.

The 'Keeping Up with the Kardashians' stars dated on and off between 2006 and 2015, but despite calling time on their romance, they have remained close for the sake of their three children - Mason, 10, Penelope, seven, and Reign, five.

Last week, the former couple spent time in Utah with their brood to celebrate Scott's 37th birthday, and sources say the pair had ''so much fun''.

An insider explained: ''Kourtney and Scott had so much fun with the kids in Utah, and the kids want them to do family trips all together more often. Scott is so happy that he and Kourtney get along so well and how easy it is with her. It's weird to everyone else, but not to them. They are really like best friends.''

The source also claimed Scott - who recently broke up with his partner Sofia Richie - has been ''flirting'' with 41-year-old Kourtney, although the beauty is ''not open to him in a romantic sense''.

They added to Us Weekly magazine: ''Kourtney is not open to him in a romantic sense, but Scott is always flirting with her and thinks she looks better than ever. The family also loves him and he's like another son to Kris [Jenner].''

Scott and Sofia, 21, were revealed to have split last week after three years together.

A source said: ''They are technically 'split' but Sofia has been in touch with Scott. There wasn't a fight or anything bad that happened between them. Sofia simply wants to do her own thing whilst Scott takes care of his health. Sofia thinks Scott has a lot on his plate right now and thinks it's best for them to be apart so he can focus on himself. She is only looking out for him and his best interest and it was primarily her decision for them to split. Sofia has been spending time with her family and has taken majority of her stuff out of Scott's house.''

However, insiders believe it's likely the former couple will get back together.

The source added: ''It's very likely they will reconcile.''