Halsey hosted her annual Halloween Party in L.A. last night and she brought along a very special guest, the one and only Avril Lavigne, for an incredible performance.

During Halsey’s scheduled performance, the two singers joined forces to perform Avril’s undeniable hit ‘Girlfriend’.

Fans were able to RSVP to the exclusive event, which Halsey hosts every single year. And she doesn’t play around when it comes to iconic costumes either.

The party was tagged on the website as “Halsey Presents: Almost Famous is an experiential Halloween Party in Hollywood, celebrating the Rockstars of the ’60s, ’70s, ’80s & ’90s.”

Admission is free, but the musician installed a mandatory donation policy for Los Angeles based charity My Friend’s Place.

During the party, Halsey came out with a wildly awesome costume for goths with an iconic Marilyn Manson look.

You can check out the post that premiered the look to the world on Instagram below.

(Also notice Evan Peters show up in the photograph, who many are speculating could be Halsey’s new partner)

During the evening, she performed a set which some fans caught footage of. This is when she brought out Lavigne for a stellar performance that luckily has been caught on camera. She also played her hit song ‘Graveyard’ during the night.

You can check out those performances in the fan-captured videos below.

Avril Lavigne brought back from the past to perform this absolute bop, the power that that has, the intelligence that that has.

What’s best is that the whole performance was done with Halsey dressed as Marilyn Manson and Avril Lavigne dressed as Madonna.

“THIS IS THE MOST ICONIC THING I’VE EVER SEEN” wrote one Twitter user, and honestly we couldn’t agree more.

And if you’re looking for the full performance of ‘Graveyard’, we have that too. Thankfully footage was captured of the song for our viewing pleasure.

What do you think of Halsey and Avril Lavigne’s performance of ‘Girlfriend’? Let us know what you think in the comments section!