Paul McCartney's latest musical project has a little bit of a modern cache to it. The vocalist revealed via Twitter that he's working with the company behind the music for the popular video game 'Halo.'

In his posting, he wrote, "I'm really excited to be working on writing music with Bungie, the studio that made 'Halo.'" He included a photo of himself in the studio working on the project.

However, Rolling Stone reports that while he may be working with the studio behind 'Halo,' the tracks that he's working on may not necessarily be for 'Halo 4.' For the most part, McCartney is a newbie to the video game world, though his image was licensed for 'The Beatles: Rock Band' in 2009.

In other McCartney news, the rocker has just lent his backing to the Humane Society International's 'Be Cruelty-Free' campaign. The vocalist stated, "If every cosmetic tested on rabbits or mice had a photo on the packaging showing these animals with weeping swollen eyes and inflamed skin, I believe everyone would leave cruelty on the shelf and go for the cruelty-free option instead." Read more about the HSI campaign and lend your support here.

More From Ultimate Classic Rock