Video shows off Microsoft's Cortana virtual assistant in action

"Hi there. I'm Cortana. I can help make life a bit easier for you." These are the first words of Microsoft's still unannounced virtual assistant codenamed "Cortana," according to a new video leaked by If it's true, this is the best look we've had of the rumored Windows Phone 8.1 service so far. The video begins by showing Cortana as a dedicated Live Tile, and then takes us through the setup process. You'll be prompted to login with your Microsoft Account, which is required to enjoy all of the service's features; according to the permissions page, Cortana will have access to sources like your location data, voice input, contacts, calendar, search history, emails and texts, browser history and more.

After you're logged in, it's time for you two to get better acquainted. To help along the process, Cortana asks a series of four questions about yourself, which the service then uses to personalize some of its suggestions and recommendations. The video also displays a new feature called quiet hours, which lets Cortana take care of your texts and calls for you while you're sleeping. We're expecting an official announcement and more details at next month's Build conference, but in the meantime you can find the full video below.