Kardashians and Jenners Look Like They Stepped Out of Taylor Swift's "Bad Blood" Music Video—See the Pics!

Sisters turned out to celebrate Kylie Jenner's Galore cover

There's no denying it: The Kardashian and Jenner women are rocking New York Fashion Week. Whether it's Kendall Jenner strutting her stuff on the catwalk or Kylie Jenner looking stylish in the front row, these Keeping Up With the Kardashians stars know how to make a statement.

It was no different at an after-party at Up & Down in NYC Monday night, where Kylie celebrated her Galore cover along with the Tart x Galore Fashion Collection collaboration. She, Kendall, Kourtney Kardashian and Khloé Kardashian channeled their inner "Bad Blood" and showed up wearing all black as if they were starring in Taylor Swift's music video. Jonathan Cheban, Tyga and Justine Skye also attended the celebration.

An eyewitness tells E! News that Pia Mia was spinning while Skye performed. Everyone else danced the night away.

"Kourtney was drinking champagne and dancing with Khloé near the DJ booth," the insider tells us. "Kourtney seemed really happy and enjoyed her night out with her sisters. She was smiling and dancing."

Kylie and Tyga "stayed close" throughout the party, and the insider adds that they were "flirting and acting really cute." Even though the E! stars went their separate ways for a portion of the evening, they all came back together to enjoy each other's company.

"Kylie was having a blast and laughing with her sisters," the eyewitness adds. The party went on until 2:30 a.m., but we're told Kendall left much earlier to get some beauty sleep.

This week has not only been special for Kendall but also for Kylie. She and Tyga have been able to put their relationship on display without having to worry. Another insider exclusively told E! News, "Kylie and Tyga have been having a really fun Fashion Week together. It just feels good for both of them to be out in the open and not hide and pretend they aren't dating. They feel way more at ease."

Since Kylie's 18th birthday and her big move, the couple has become even more serious. "They are both in such a good place in their relationship," the source said. "Kylie turning 18 and getting her new place has opened up different parts of their relationship."

Congratulations to Kylie and Kendall on their big week!

Tune-in to new episodes of Keeping Up With the Kardashians starting Sunday at 8 p.m.