The rumors are now officially true (well, one of the rumors, anyway). Microsoft announced that it will be showing off "a new generation of Xbox" at its Redmond, WA campus starting at 10am PST on May 21.

An invite sent to press and industry watchers today tells recipients that "Don Mattrick and the Xbox team invite you to the Xbox campus for a special unveiling." A note sent out to Xbox owners on Microsoft's official e-mail list (and on the Web) mentions that the event will be streamed live on Spike TV and Xbox.com, as well as through Xbox Live itself.

Microsoft representatives are obviously remaining tight-lipped about what will be announced and shown, but they are recommending that press block off the entire day for "interviews and activities" (including playable demos? Microsoft wouldn't say).

The event comes just weeks before the industry's annual E3 confab, which starts on June 11 and usually features a pre-show press event from Microsoft. It's currently unclear whether this "new generation" reveal is a replacement for that event or the first part of a quick one-two punch of Microsoft gaming announcements. Microsoft's official entry into the next-generation race comes a little more than three months after Sony kicked things off with the unveiling of the PlayStation 4 in New York City. Sony still has yet to reveal that system's precise launch date and price point or allow it to be widely playable by the press.

The lack of official word from Microsoft on the Xbox's successor, codenamed Durango, hasn't dampened talk about the new system. Persistent leaks and rumors have given supposed details about everything from the technical specs and supposed TV integration to one-time install discs and potentially controversial "always-on" Internet requirements for the system.

Ars will be there with a liveblog and full coverage as Microsoft unveils its next-generation plans.