After a somewhat lengthy preview period, Microsoft is taking the wraps off of its Slack competitor, Microsoft Teams, today. To mark the chat app's global availability, Microsoft is also holding a livestream celebration in which Office Corporate Vice President Kirk Koenigsbauer a mystery special guest will talk about what's new with the service, teamwork, and more. That's set to kick off bright and early at 8:30 a.m. PT / 11:30 a.m. ET, and you can tune in below.

Even since launching in preview in November, Microsoft Teams has enjoyed its share of success. It's available in 19 different languages across some 181 markets worldwide, and Microsoft noted in its launch announcement that it's already in use by 50,000 organizations worldwide.

Teams itself has morphed with more than 100 new features added ahead of launch, Microsoft says. Those include audio calls on mobile, video calls on Android, and much more. As part of the launch, Microsoft also announced that it has partnered with SAP and Trello to bolster teamwork and analytics.

There are plenty of updates coming down the line, with Microsoft promising regular feature updates. For now, Microsoft Teams is now officially available for Office 365 business users to check out worldwide. And if you have questions about Team, Microsoft says it will be holding an AMA on its Tech Community site at 9 a.m. PT / 12 p.m. ET.