Microsoft's much-anticipated digital assistant, which is expected to rival Apple's Siri and Google's Google Now, has surfaced in a leaked video. We’ve heard all about what Cortana is capable of doing, thanks to many rumours and reports, but now we finally have a first-hand look at the service.

The video, outed by UnleashThePhones, shows Cortana on a pre-release build of Windows Phone 8.1. It initially reveals Cortana as a Live Tile, and then walks us through her setup process. It appears you'll first have to login with your Microsoft Account. Then, as seen in the permissions page, Cortana can access your information including bits like location data, voice input, emails, texts, contacts, calendar, search history, browser history, and more.

From there, Cortana will ask you four questions (an example question includes: "what are a couple of the most enjoyable parts of your everyday evenings?"). Your answers will, presumably, help Cortana to learn more about you and customise recommendations. Another handy feature leaked in the two-minute video is a do-not-disturb-like function called quiet hours. It enables Cortana to handle your texts and calls while you're snoozing.

And that's about all the video shows. However, YouTube user Yash Maheshwari provided the following description for the leaked video that he or she posted: "Cortana is the hotly anticipated Digital Personal Assistant Microsoft is introducing with Windows Phone 8.1 as Windows Phone's answer to Siri and Google Now. Here is a brief glimpse at the run-up to configuring Cortana."

READ: Cortana to be unveiled as Microsoft's version of Siri

We will likely hear more about Cortana, including her voice and more details, at Microsoft's Build conference scheduled for next month. In the meantime, check out the newly-leaked video above.