UPDATE 1PM GMT: CD Projekt Red has responded.
The mobile game has been in development for a year by a standalone team, I was told, and an official announcement is going to happen "very soon". It will coincide with the launch of a beta test.
"Smartphones and tablets are truly powerful platforms these days and are finally giving us the ability to develop mobile games we would like to play ourselves; games that are taking full advantage of newest smartphone and tablet technologies, and offer the quality level that we, as a studio, are always aiming to achieve," co-founder Adam Kiciński added.
ORIGINAL STORY 11.30AM GMT: Polish Witcher developer CD Projekt has announced a mobile game that will be released this year.
"For several months, along with an external partner, we worked on another, unannounced project, which we plan to launch this year," revealed CD Projekt in a management report, reported by (and English translation provided by) Eurogamer Poland.
"It's a multiplatform mobile game, made with advanced technological capabilities of tablets and smartphones in mind. Thus, we are entering a completely new territory in terms of gameplay and business model, realising our strategic plans to enter the mobile gaming market."
It's not specified as a Witcher game, but in a video conference just finished, CD Projekt said it was licensing "a brand" to the external partner. What else could it be besides The Witcher? Cyberpunk 2077?