Wait for us! Kylie Jenner holds King Cairo's hand as duo sprint to private jet for family trip to Costa Rica

She may be his stepmother one day.

And Kylie Jenner proved she already has a strong bond with her boyfriend Tyga's son King Cairo as she doted on the tot on Thursday.

The 19-year-old reality star was spotted holding hands with the four-year-old boy as they prepared to jet off to Costa Rica from Los Angeles with the rest of the Kardashian clan. 

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Come with me! Kylie Jenner took her boyfriend's son King Cairo by the hand as they sprinted to board a private jet in Los Angeles on Thursday

Kylie held on tight as she burst into a run across the tarmac with King running as fast as he could behind her. 

The Lip Kit mogul was clad in an appropriately sporty ensemble of black tracksuit bottoms and a red sweater. 

Her brunette locks were tied up into a messy bun.

Also spotted at Van Nuys airport was Kylie's sister Khloe Kardashian, her mother Kris Jenner and Kris' boyfriend Corey Gamble.

Family trip to Costa Rica! The duo joined family members including Kylie's mom Kris Jenner, sister Khloe Kardashian and of course King's dad Tyga who Kylie's dating

Emulate Kylie's casual style in a Vetements oversized sweatshirt

Kylie Jenner prepared to take flight with the rest of the Kardashian klan to Costa Rica and the beauty entrepreneur dressed comfortably in a Vetements hoodie and Yeezy sweatpants and sneakers.

The Lip Kit creator is a huge fan of the brand having been spotted wearing their pieces on numerous occasions and so are the rest of her sisters.

This particular creation is part of a collaboration with sportswear label Champion and features an on-trend oversized silhouette, extra long sleeves and an undone hemline.

Get it for $880 by clicking through to Matches Fashion (right) or if you're not keen to spend so much, check out the affordable styles we've selected below.

Team with leggings and stiletto ankle boots to capture that Kardashian essence.

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Off to warmer climes: Tyga, 27, was spotted wearing a graphic print white t-shirt as he strolled across the tarmac

Of course, King's dad was there too.

The 27-year-old rapper wore a white graphic print t-shirt as he chilled out listening to music while letting his girlfriend take over mom duty. 

Tyga shares King with ex-fiancee Blac Chyna, who is now engaged to Kylie's brother Rob Kardashian.

The couple welcomed their first child together, daughter Dream, in November.  

Meanwhile Kylie is set to launch The Valentine's Collection to Kylie Cosmetics next week.

The KUWTK star - who opened her beauty empire last year -has continued to expand her make-up brand and has taken to social media to reveal the new products she will be launching on her e-store on February 2, just in time for Valentine's Day on February 14.

Bond: Tyga shares King with ex-fiancee Blac Chyna (now engaged to Kylie's sister) but it seems like Kylie loves to dote on the tot

Quick! Kylie and Cairo excitedly ran ahead of the group 

All aboard: The 19-year-old reality star helped the four-year-old boy up the steps

Alongside an image of the lip kit package with red glitter lips emblazoned on the front, which the brunette beauty shared on her Instagram account, she wrote: 'Just revealed The Valentines Collection on my Snapchat this is my favorite collection so far! Hope you guys LOVE IT launching February 2nd ... 3pm pst @kyliecosmetics (sic).'

The cosmetics company has also broadcasted the news on their photo-sharing site.

The clan: Also spotted was Kris' boyfriend Corey Gamble who matched Kylie in a red top

Casually clad: Kylie was seen in a sporty ensemble including tracksuit bottoms and a red sweater

Alongside the same image, they wrote: 'THE VALENTINES COLLECTION ... coming FEBRUARY 2nd .. 3pm pst.(sic).'

And Kylie Cosmetics have teased the upcoming capsule will include the rouge shade, but also a box set of four mini lip products.

They captioned an upload of the forthcoming items: 'Red Minis?! Yes Please ... #ValentinesCollection #February2nd (sic).' 

Wrong jet? The couple were seen walking away from the plane as Kylie carried Tyga's boy in her arms

Bold look: Kris, 61, made sure to stand out in a tropical print tracksuit

Family time: Khloe looked stylish in black as she boarded the jet while Kourtney carried son Reign, two

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