Kylie Jenner helped her sister Kim Kardashian promote her SKIMS shapewear line

Whoa, Kylie Called Out Kim K For Skipping Her Skims Shoot In A New 'KUWTK' Promo

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Sisters are forever — unless they blow you off for a vacation in Costa Rica, that is. In a new promo for Keeping Up With the Kardashians, Kylie Jenner and Kim Kardashian go head to head, and it's all over a SKIMS photo shoot. Apparently, Jenner was helping her sister promote her new shapewear line, but when Jenner showed up for the shoot, Kardashian was nowhere to be found. No, Kardashian wasn't running late. In fact, she wasn't even in Los Angeles. Kardashian was busy vacationing in Costa Rica, which didn't sit well with Jenner. Kylie Jenner called out Kim Kardashian for skipping her SKIMS shoot and it was so awkward.

Before I get to the sisters' confrontation, let me talk about Kardashian's SKIMS shapewear line because there was a lot of drama surrounding the launch. First, it was originally called "Kimono," which referenced both Kardashian's first name and the traditional Japanese garment. When Kardashian announced the original name on June 25, fans accused the star of cultural appropriation, leading Kardashian to rename her product to "SKIMS."

On Aug. 26, Kardashian released a statement about the name change that read:

My fans and followers are a huge inspiration to me – I’m always listening to their feedback and opinions, and am so grateful they shared their ideas for a new brand name. After much thought and consideration, I’m excited to announce the launch of @SKIMS Solutionwear™ coming September 10. I love the idea that the pieces will be the closest thing to someone’s skin, skimming with amazingly soft and supportive fabrics which accentuate the best parts of our bodies. Available in sizes XXS - 5XL, SKIMS Solutionwear™ is for every body. SKIMS.COM.

Through all of the controversy, Kardashian's sisters had her back. On SKIMS' Sept. 10 launch date, the Kardashian-Jenners promoted the line on their social media pages. Jenner even went so far as to star in a SKIMS advertisement. Jenner shared her promo clip on Instagram, which showed her modeling different SKIMS garments.

You can watch Jenner's SKIMS ad below.

While fans probably thought there was nothing but love between Jenner and Kardashian behind the scenes, there was actually a small feud that happened between them. Jenner expected her sister to be there for her shoot, but Kardashian was vacationing in Costa Rica instead.

In a new promo clip for the Nov. 3 episode of KUWTK, fans see Kardashian riding a speed boat in the ocean while Jenner frantically asked her where she is. "You're not at the shoot?" Jenner asked frantically, to which Kardashian replied, "No! I'm in Costa Rica!"

Jenner then pulled a face and she did not look happy at all.

Before you think Kardashian just blew off her sister, know that Kardashian took a much-needed vacation due to all the stress she'd been under.

"My schedule is so hectic," Kardashian said in the clip. "I just need a day with my kids."

While fans only saw a glimpse of the drama in the clip, they can find out what really went down when Keeping Up With The Kardashian airs Nov. 3 on E!