Kylie Jenner and Sofia Richie - who is dating Scott Disick, who is the ex-partner of Kylie's half sister Kourtney Kardashian - have always been friends but their bond is said to be even stronger now.
A source told Us Weekly: "Kylie and Sofia have always run in the same circle and are very close in age, so they've bonded a lot through the years.
"They've always been in the limelight, lived very similar lifestyles and grown up around a lot of the same people. They've gotten a lot closer as of late now that the Kourtney, Scott and Sofia drama has died down. Once any drama between Kourtney and Sofia blew over, Kylie felt more comfortable spending girl time with Sofia again."
Scott and Kourtney - who have children Mason, nine, Penelope, seven, and Reign, four, together - have remained close and Sofia previously told pals she is "not threatened" by fans who want to see Scott reunite with Kourtney.
A source previously said: "(Sofia) does not feel threatened or jealous whatsoever when it comes to fans asking for Scott and Kourtney to get back together. In fact, she completely understands where they're coming from and is not surprised at all by their reaction. Sofia is one of the most confidant 20-year-olds you will ever meet, so she is not worried about all the talk about Kourtney and Scott getting back together.
"She is friends with Kourtney and respects her both as a person and a mother and she is in love with Scott and trusts that their relationship is solid and he will not go astray with anyone - let alone his baby mama. Sofia is cool with it all, cool with all the chatter because she knows that Scott is hers and it will remain that way forever. She is as far from being worried or concerned as one could possibly be. She has better things to worry about than things that are never going to happen."