Just four months after launching the AI chatbot for Premium and Premium+ X users only, the billionaire businessman has decided to make the current version free to all.

A blog post read: "Since launching Grok-2 in August, we have been hard at work improving Grok on X, adding new features like web search, citations, and our recent image generator, Aurora.

"Over the past few weeks we have been quietly testing a new version of the Grok-2 model, which is three times faster and offers improved accuracy, instruction-following, and multi-lingual capabilities.

"Today we are excited to announce that we are beginning to roll out this new version of Grok-2 to all users on X for free."

The company reassured those who have paid for subscriptions to the micro-blogging site: "As always, Premium and Premium+ users get higher usage limits and will be the first to access any new capabilities in the future."

It comes as Musk's firm tests out a new version of the chatbot.