REUTERS/Jim Young
The device, which has not been announced or officially recognised by Microsoft, would be roughly designed around the Surface tablets, could be aimed at businesses, and would aim to turn the company's failing smartphone efforts around.
Windows phones currently account for around 1.7% of the worldwide smartphone market, according to Gartner, and it has become a point of contention for Microsoft as a whole.
Here's everything we know about the Surface Phone: