Google's Pixel-branded smartwatch has been rumoured for years, but the speculation has significantly increased recently, with not only real-world images of the device appearing, but pictures of the Pixel Watch on a wrist surfacing too.

The latest report surrounding the Pixel Watch comes in the form of Bluetooth certification - something all devices offering Bluetooth have to go through before launch.

The listing appeared on Bluetooth Special Interest Group (SIG) and it refers to a device called BT Wearable Design-Controller Subsystem, which is thought to be the Pixel Watch. The listing mentions three models - GWT9R, GBZ4S, and GQF4C - though it is not currently clear whether those three models are simply different cellular bands for example, or whether they refer to different models with varying features and different sizes.

In terms of certifications, Google also recently submitted the Pixel Watch name to the US Patent and Trademark Office so the evidence for the smartwatch is certainly mounting up. While nothing official has been said as yet, it is expected that the Google Pixel Watch might see an announcement at Google I/O, which kicks off on 11 May.

Based on the leaked images of the device, the Pixel Watch will feature a round, minimalist design with a heart rate sensor on the rear and a crown in the centre of the right edge. It is expected to run the Wear OS 3 software, developed by Google and Samsung. You can read all the Pixel Watch rumours in our separate feature.