[UPDATE] Microsoft has confirmed that the leaked theme music and Warzone images are indeed legitimate. In a statement, Microsoft called the leak "unfortunate."

"It's unfortunate when work-in-progress content leaks, but this Halo 5: Guardians content is part of our ongoing private, external testing for multiplayer. We will continue to rigorously test Halo 5: Guardians to ensure the best possible experience for fans at launch."

The original story is below.

The Halo 5: Guardians theme music and first images of the menu for its large-scale Warzone mode have leaked.

First, the theme music. According to the Halo Memes YouTube account, the Halo 5 beta from December 2014 received an update this week that includes the audio you hear below for the main menu. The beta is still not playable, but you can listen to the lovely music through the video embed below.

According to Halo boss Frank O'Connor, the bulk of Halo 5's soundtrack was composed by veteran composer Kazuma Jinnouchi, who previously worked on Metal Gear Solid 4: Guns of the Patriots.

The other bit of Halo 5 leaked information today is the game's menu screen for the 12v12 Warzone mode, which comes by way of this video with images compiled on NeoGAF.

The images (click through the gallery below to see them all) show off Warzone's title screen, as well as others for customization (armor and weapons), general settings, and more.

We've followed up with Microsoft in an attempt to confirm the authenticity of the music and images.

Halo 5 launches on October 27 exclusively for Xbox One.