We all know history repeats itself time and time again: it's true for music (the classic rock influences on One Direction's latest album, for example), movies (the "Ghostbusters" reboot and several other sequels), fashion (queen Mariah Carey's influence) and more.

So at the American Music Awards on Sunday night (Nov. 22), it wasn't all that shocking to see throwbacks and callbacks to years' past. It was, however, an overwhelmingly '90s-inspired affair. From surprise reunions (J. Lo and Diddy! "Clueless!") to style staples (oh HEY, snap barettes) there was plenty of '90s nostalgia happening inside the show. Check out these nine examples:

The show kicked off with host Jennifer Lopez singing “Waiting for Tonight.”

J. Lo’s 1999 club banger (you know, the one with the rainforest rave in the music video) was alive and well at last night’s show.

After her opening number, Lopez gave a shoutout to five legendary ‘90s performers.

After explaining what hosting the show means to her and how it’s a dream come true, she called out Whitney Houston, Michael and Janet Jackson, Madonna and Prince as some of the show’s most memorable and celebrated artists (bonus: Prince was even there!).

Alanis Morissette returned!

And not only that, but she celebrated the 20th anniversary of her album Jagged Little Pill with a dual-generational performance of “You Oughta Know” alongside Demi Lovato. So, yes, Demi basically lived every angsty ‘90s girl’s dream last night.

Paula Abdul and Donnie Wahlberg presented together.

They presented Ariana Grande with the award for Favorite Pop/Rock Female Award, a prize Abdul received in both 1990 and 1992 — around the same time that Wahlberg was killin’ it in New Kids On The Block.

Celine Dion proved she’s still the reigning queen of power ballads.

The iconic singer paid tribute to the victims of the recent Paris terrorist attacks by singing Edith Piaf’s “Hymme A L’amour.” Basically, it was the hardest we’d cried since her weep-worthy “Titanic” song, “My Heart Will Go On.”

There was a “Clueless” reunion!

Alicia Silverstone (Cher Horowitz herself) and Jeremy Sisto (“Rollin’ with the Homies” enthusiast Elton) teamed up to introduce Gwen Stefani’s performance and to give us all the nostalgic gushiness.

On the style front, Chloe Grace Moretz wore snap barettes in her hair.

These were staples of every ‘90s girl’s closet, along with that black ribbon choker.

And Justin Bieber rocked a Nirvana shirt.

Who knew he was such a grunge fan?!

Diddy and Jennifer Lopez were the friendliest exes ever.

When Sean Combs appeared onstage to present an award to Bieber, he sweetly asked the crowd, “Can we give it up for Jennifer Lopez one time?” As if that wasn’t enough to make us giddily flash back to their 1999-2001 romance, the two then hit the after party together, where it was all smiles. #ExesGoals.