It looks like there’s another reason to believe that Microsoft has been secretly working on the long-rumored Surface Phone. An engineer for the company who is based in China apparently slipped recently and dropped a hint at the highly anticipated device.

Over the weekend, a Microsoft engineer took the time to respond to a complaint raised on a Chinese Q&A site called Zhihu about the poor integration of the Cortana digital assistant on Android. The engineer used the Microsoft Asia Research Institute’s Cortana support account to reply to the complaint and initially made a mistake of mentioning the better implementation of Cortana on the Surface Phone.

In the engineer’s statement, he said that the problem with the integration of Cortana on Android was the lack of permissions on the operating system. He then noted that he is actually looking forward to seeing the better performance of Cortana on the Surface Phone, according to MSPoweruser.

It took some time before the engineer realized that he may have blurted a confirmation about the rumored Surface Phone. He later retracted his statement and edited the thought of it by saying that he himself isn’t really sure if the Surface Phone is real. He then maintained that the Cortana team is working to make the assistant better.

Reports about Microsoft developing a Surface Phone have been going on for years now. The device is believed to be running a new operating system called Andromeda, which is said to be a combination of the Android and Chrome operating systems for mobile devices. Given that the phone is being associated with Surface, expectations are high for it to launch with premium design, specs and features.

According to Phone Arena, the latest speculation about Microsoft’s Surface Phone is it could be a smartphone-tablet hybrid. This means the device is expected to be pocketable as a smartphone, but it could be folded out to become a tablet. Last month, Microsoft actually filed a patent application for a folding Surface device, and the patent has since sparked rumors that Microsoft could finally be introducing the Surface Phone very soon.

Meanwhile, Microsoft isn’t the only company that’s rumored to be preparing a foldable phone. South Korea tech giant Samsung is also gearing up for the unveiling of its Galaxy X foldable phone this year. The company’s mobile chief, Koh Dong-jin, announced last year that Samsung is planning to launch its foldable phone in 2018.