Launching on Monday (November 12), the TV advert features the This Morning presenter revealing that when she is not on TV, she likes to spend time at home cooking for her family.
Willoughby also discusses various features of the new Windows Phone 8, including Kid's Corner, which allows parents to set what their children can access on their smartphone.
The advert will run from Monday until mid-April on primetime shows, such as The X Factor, I'm a Celebrity... Get Me out of Here!, Made in Chelsea, and Willoughby's own show, Surprise, Surprise.
It was filmed at a stately home in Hampstead.
At the Windows Phone 8 launch last month, Microsoft enlisted Jessica Alba to showcase how she uses features such as Kid's Corner on her Windows Phone mobile device.
> Windows Phone 8 review - improved but lacking
> HTC Windows Phone 8X review - a worthy flagship
Watch the Windows Phone advert below: