The rumors have been confirmed. Technology stalwarts Nokia and Microsoft are forming a strategic partnership that involves Nokia adopting Windows Phone as its primary smartphone platform, a move that could steal marketshare from major rivals like Apple and Google.

Whereas Nokia has long relied on its own proprietary software for its devices, the company now plans to guide the future of Windows Phone by lending its expertise on matters such as hardware design, language support, and help bring Windows Phone to a larger range of price points, market segments and geographies.

As for functionality, Bing will power Nokia’s search services across Nokia devices and services. Microsoft adCenter will provide search advertising services on Nokia’s line of devices and services, and Nokia Maps will be at the center of Microsoft’s mapping services.

In an open letter, Nokia CEO Stephen Elop and Microsoft CEO Steve Ballmer said: “Today in London, our two companies announced plans for a broad strategic partnership that combines the respective strengths of our companies and builds a new global mobile ecosystem. The partnership increases our scale, which will result in significant benefits for consumers, developers, mobile operators and businesses around the world. We both are incredibly excited about the journey we are on together.”

The news falls on the heels of earlier reports from All Things Digital, Bloomberg News, and the Wall Street Journal that the Nokia CEO had “held talks” with both Ballmer and Google CEO Eric Schmidt about integrating either the Windows Phone or Android mobile platforms into new Nokia handsets.

Elop’s plans to shake things up first came to light earlier in the week when technology blog Engadget published a leaked internal memo that is said to have been written by Nokia’s newly appointed chief executive officer. According to the blog posting, Elop compared the struggling mobile phone manufacturer’s plight to that of a man standing on a “burning platform” and attempting to figure out whether to leap into icy waters.