As I exclusively revealed last year, Microsoft has been slowly killing its Zune brand and switching its media-related services over to Xbox branding. Today, the company confirmed this move in a blog post, indicating that it would have more to share about this transition next week at the E3 trade show.

“The Xbox has arrived at an important inflection point in its growth and development,” Microsoft chief marketing officer Yusuf Mehdi writes in a post to the Official Microsoft Blog. ”In particular, in the last year, the Xbox has transcended from a gaming console to a broad entertainment device inclusive of movies, TV, music and sports.”

Mehdi goes on to describe the transition that I first discussed last year: After shutting down hardware development on the eve of the Zune HD launch in 2009, it began work dismantling the Zune team and discontinuing use of the Zune brand. When I first caught wind of these changes, Microsoft wasn’t sure which brand, Windows or Xbox, it would use for the former Zune services. But since then, the company settled on the Xbox brand, which resonates more with consumers.

And while this transition has in fact already happened, Mehdi’s post is the first from Microsoft to confirm it.

“This year, Xbox becomes the premium entertainment service for Microsoft,” he writes. “Whether on your PC, tablet, TV or phone, Xbox will be a gateway to the best in music and video, your favorite games and instant access to your friends. With the launch of Windows 8, we’ll bring Xbox entertainment to everyone. With Xbox on Windows 8 devices, we rapidly accelerate the reach of Xbox entertainment from more than 60 million people to hundreds of millions of people worldwide.”

“We understand that entertainment has become a multi-screen experience where you and your friends are watching TV, listening to music, and playing games while interacting with your tablets and phones in new ways,” he continues. “We’ve got ideas for making all the entertainment you love more personal, interactive and social across the devices you love—and on the phenomenal Windows 8 devices that are to come.”

Mehdi then writes that Microsoft will be showcasing its Xbox services on Windows 8 next week at E3. A live event discussing these plans will be viewable for the first time via Xbox LIVE on Monday, June 4, 2012 at 12:30 pm ET.