Sir Paul McCartney is apparently playing a part in Bungie's upcoming Destiny franchise. The former Beatles singer-songwriter posted on his Twitter account today that he's "really excited to be working on writing music with @bungie, the studio that made Halo."

McCartney posted this picture along with his Bungie tweet.

Although Bungie hasn't officially announced its next project, the studio's contract with Activision was outed as a result of the publisher's legal fight with Jason West and Vince Zampella. The contract called for Bungie to create Destiny, a series of four "massively multiplayer-style…sci-fantasy, action shooter games," to be delivered every other year beginning next fall. In between those releases, the studio was expected to produce downloadable expansion packs under the code name "Comet."

Bungie hasn't detailed release plans or platforms for its first series for Activision, and these plans were only current as of the April 16, 2010, signing of the contract.

The 70-year-old McCartney has been involved in games before, most notably with the release of The Beatles: Rock Band. In an interview with German outlet Die Zeit earlier this year, McCartney said he didn't game himself but was interested in the medium as a way to expose people to new music.