Kylie Jenner wishes her BFF Stassie Karanikolaou a Happy Birthday with throwback photo of the friends wearing matching pajamas

Kylie Jenner celebrated her BFF Stassie Karanikolaou's birthday with a throwback exchange of tweets featuring her sister Kendall Jenner.

In it, Kendall teased Kylie about how close she is with her bestie, asking her sibling how many forms of communication the two young women need. 

Kylie pointed out that the exchange was from 2012 and nothing has changed between the two women, who enjoyed a night on the town celebrating Stassie's birthday. 

The mom of two also shared a photo of herself and Stassie goofing off in PJs when they were younger. 

Not to be left out, Kim Kardashian pulled some photos from the past to share birthday wishes for the socialite.  

The two ladies enjoyed a night on the town in celebration of Stassie's 27th birthday on Saturday night as well.

They slipped into two body con dresses and hit the town together, later sharing photos from their night out on Instagram.

'for liiiiife. ♾️♾️ @staskaranikolaou,' she captioned the post, adding a red balloon emoji.

The young women have been close friends since they met in middle school in a Barnes & Noble bookstore in Calabasas when they were 13.

'She's definitely my oldest friend,' Jenner said of Karanikolaou on the season 3 finale of The Kardashians on Hulu.

'We grew up together, we've been through so much together. She's like a sister to me.'

These days the best friends have a pair of famous boyfriends too, with Kylie linked to Timothée Chalamet for the past year and Stassie dating To All The Boys I've Loved Before's Noah Centineo. 

Earlier this month, it was revealed that Jenner and Chalamet's romance is 'still going strong' after the pair recently enjoyed a romantic double date in New York City late last month in May.

A source told People that the pair prefer to keep their relationship 'low-key' and mainly out of the public eye.

The couple's latest outing comes shorty after Kylie debunked pregnancy rumors when speculation swirled on social media following comedian Daniel Tosh alleging the reality star was expecting her first child with Timothée.

It was also revealed that Kylie's loved ones are concerned that she may get her heart broken, a source told DailyMail.com exclusively.

'Kylie is trying to hold onto her relationship with Timothée, but those around her fear it is becoming evident that he's just not as invested in their relationship as she is anymore.'

The insider added, 'Kylie is madly in love with Timothée and she put so much into this relationship. She went so public with their romance because she was sure it would last.

'But those closest to her feel he doesn't make her a priority and her sisters are now telling her to walk away, but she can't.'