Khloé Kardashian Wears Sexy Crystal Dress to Kourtney Kardashian's 40th Birthday Party

Kaitlyn Frey

The Kardashians know how to throw an epic party. From the décor to the guest list and of course, the outfits, the famous family doesn’t skimp when it comes to details. And Khloé Kardashian made sure to bring her fashion A-game to celebrate Kourtney Kardashian‘s 40th birthday at the star’s major bash on Thursday night.

Khloé and her stylist Janelle Miller teamed up with Kuwait-born designer Yousef Al-Jasmi, known for his intricate embellished designs, to make a custom look for the star. Al-Jasmi constructed a sparkling high-neck column dress covered in Swarovski crystals and beads with a matching headpiece, which he says is valued at $6,500. And according to Al-Jasmi, the reality star, 34, knew exactly what she wanted right from the start.

“Both Khloé and Janelle were very involved, sending over screenshots from my Instagram and inspiration photos to work off of,” Al-Jasmi tells PEOPLE exclusively. “They knew the exact look they wanted to achieve, so we worked very closely to perfect the design, from the color to crystals.”

Miller, who has been styling Khloé for approximately one year after previously assisting the star’s former stylist Monica Rose, agreed with Al-Jasmi.

Kim Kardashian/Instagram

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“[Khloé’s] very involved. She knows exactly what she likes and what looks good on her. Even though I like to think I have all the ideas!” Miller tells PEOPLE exclusively with a laugh.

Al-Jasmi says the vibe the star wanted to go for was “sexy, elegant and overall fun, mimicking her personality.” Miller adds: “I love that Yousef instantly gets it! Khloé will send over inspiration of what she wants and he just gets it. He has designed for her so many times that he just seems to understand her vision from the start.”

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Though the gown might appear to be heavy due to all of the beading, the designer says it was “actually very lightweight.”

Khloe Kardashian/Instagram

He adds: “While it’s extravagant with the mix of Swarovski crystals and beaded elements, it’s comfortable to wear. It almost becomes a second skin.”

Ultimately, Al-Jasmi says he was honored Khloé chose him to create her gown for such a special family occasion. He says, “This is the first time making something for her since she gave birth to True. It’s very humbling that she chose to wear my design for [Kourtney’s birthday].”

Khloé is such a fan of Al-Jasmi that she wore a similar dress by the designer to Kris Jenner’s 60th birthday party in 2015. For The Great Gatsby-themed party, Khloé chose an embellished curve-hugging silver gown with matching headpiece that is reminiscent of her look worn to Kourtney’s soirée.