Kylie Jenner's Christina Aguilera Costume for the Singer's Birthday Party Was Everything

What do you get a pop star who has everything? A time machine.

Or, just show up to their birthday party dressed like a younger version of the person-of-the-hour. Kylie Jenner's Christina Aguilera costume that she wore this weekend was just that. Also, it was an unexpected surprise and a total delight.

You might be worried that the singer and Voice judge, who officially turns 36 next Sunday, might be taken aback by the sartorial statement. No shade though, because Jenner dressed as a vintage Xtina, circa 2002, at the request of the birthday girl, according to Instagrams from the reality TV star and beauty mogul. Jenner revealed her costume/party outfit on social media, and she was the spitting image of the "Dirrty"-era Christina—complete with ass-less chaps, blue contacts, blonde extensions and all.

Let's just hope this means that with the launch of her lip kit wall, Kylie's now taking a side job as a throwback Xtina impersonator that we can hire for all our birthday parties.

See how Jenner compares to the OG Xtina, who originally wore the black-and-yellow revealing ensemble to perform on an MTV's TRL special, Christina Aguilera Stripped. So many nostalgia feels.

Composite. kyliejenner/Instagram, Theo Wargo/Getty Images

The two celebrities got very cozy during Aguilera's bash.

Jenner also Snapchatted her outfit, set appropriately to Aguilera's 2002 hit song.

And she gave fans a look inside the colorful birthday bash, which had a light-up disco-style dance floor.

This isn't the first time Jenner has gotten down and "Dirrty." The makeup mogul caught Xtina's attention when she dressed as the pop star for Halloween a few months ago. Jenner—who we have to admit, made us do a few double takes for the similarities—apparently loved her singer persona so much she captioned a video of her dancing to the Aguilera song, "Can I be XTINA forever?"

Clearly, Aguilera is Jenner's genie (in a bottle) for granting the 19-year-old's wish, by asking her to channel the persona yet again.

Now watch Christina Aguilera's beauty transformation: