10/13/2015 04:12 EDT | Updated 10/13/2015 04:59 EDT

The Kardashian-Jenner's Celebrate Cosmopolitan's 50th Birthday With Snapchat

Stop the presses: Kim Kardashian snapchatted for the first time at the party.

Happy 50th birthday to Cosmopolitan magazine!

To celebrate their half-century of existence, the glossy had a trendy soirée on Monday night in Los Angeles with some pretty fabulous guests. Included? None other than the Kardashian-Jenner girls.

Kris Jenner, along with her daughters Kim Kardashian, Khloé Kardashian, Kourtney Kardashian and Kylie Jenner (sadly, supermodel Kendall couldn't attend *tear*), stepped out together at the party to celebrate their cover for the magazine's November issue. The controversial 16-paged spread, which dubbed the Kardashian-Jenner clan "America's First Family," hits newsstands today.

As we know, the Kardashian-Jenner ladies are a stylish bunch and are always #onfleek. But it seems like the youngest member, Kylie, did not receive the group email that specifically stated to wear black to the event. Oh, Kylie.

I didn't get the "wear all black" email

A photo posted by King Kylie (@kyliejenner) on

The 18-year-old, who is back to blond, opted for a short, cream-coloured dress, while her mother and three sisters each wore a different black ensemble. We particularly love Khloé's daring frock -- a thigh-high slit and plunging neck combo? Fierce.

On a night which saw Kim take to Snapchat for the first time (stop the presses!), our new favourite app was kind enough to bless us mere mortals whose invitations to the event got lost in the mail with a live Snapchat story entitled, "Cosmo and Kardashians."

From Khloé convincing us to buy her cover of the mag, to Kim and Kourtney blowing out candles on a ginormous cake, we take a look at some of the Cosmo birthday party highlights as documented on Snapchat.

The "It's Time To Party!" Snap...

It feels like we're ACTUALLY on the red carpet!

The Kris Jenner Welcome Snap...

Mother of the Kardashian-Jenner kingdom welcomes viewers to a birthday party we don't want to miss!

The Mother-Daughter Snap...

Kris and Kylie share a moment on the red carpet. N'aww.


You might want to mark this day in your calendars, because the queen of selfies, who doesn't have a personal Snapchat account, took hold of the phone to say hi to viewers and announce it was her first time test driving the app.

The "Make A Wish!" Snap...

Kourtney, Kim and editors from Cosmo Magazine blow out the candles on a cake that looks too delicious for words.

The Khloé Takeover Snap...

Khloé shows off her gorgeous individual cover of the mag.

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