Users can apply for the closed beta by visiting the Witcher 2 website. Applications must be submitted before September 30.
RedKit enables users to build new environments, add non-playable characters and create dynamic adventures.
All of The Witcher 2's development tools will be open to users, including full texture packs, custom full day and night cycles, and vegetation.
Modders will have the ability to add their own quests with conditions that change based on player behaviour.
Inserting a quest to rid a village of monsters, for example, will see the monsters attack the settlement, killing its inhabitants if Geralt leaves before it's complete.
RedKit will be free to PC users when it releases next year.
CD Projekt is currently working on Cyberpunk, which takes place in a futuristic setting filled with cybernetic implants and high-tech weaponry.
Launch dates and platforms are still to be announced, although the game is expected to release for the PC.
> The Witcher 2: Enhanced Edition review: An engaging fantasy epic
Watch a trailer for The Witcher 2: Enhanced Edition below: