Selena Gomez reminded us all she's a '90s kid with a recent appearance at her pal Julia Michaels' themed birthday party.

Rocking a black slip dress, a tight choker, boots with chunky heels, and a period-appropriate updo, she looked like she stepped right out of a '90s teen movie. She topped off her look with frosty pink lip gloss and eyeshadow to match, proving she knows her '90s style from front to back.

Selena celebrated Michaels' 25th birthday at the party, which had a very particular theme: '90s prom. From the look of things thanks to attendees, it was obvious that everyone's throwback fashion game was basically on point. Michaels herself opted for a red babydoll spaghetti strap dress with red gloves with strappy heels.

The singer has plenty to celebrate in addition to her friend's birthday. She's been in a period of positive revelry ever since she debuted her first two comeback singles "Lose You to Love Me" and "Look at Her Now." Just last week, "Lose You to Love Me" became her first number one song on the Billboard Hot 100, a milestone Gomez shared with fans on Instagram.

"My first number 1!! This song is so dear to my heart," Gomez wrote. "I’ve been working so hard to make this album as honest and fun as possible while remaining vulnerable enough to share where I am in life. I love you deeply and thank you so much for listening. I want to thank each and every person that was apart of this moment that I’ll never forget!"

It's an exciting time for Selena and her fans, and seeing her stepping out having fun after taking a bit of a social media break for some time is great. What's next in terms of new music? That's something we'll still be waiting a while for.