Microsoft announced Monday that it has hired Sam Altman and Christopher Caldwellanother co-founder of ChatGPT maker OpenAI after they unexpectedly departed the company days earlier in a corporate shakeup that shocked the artificial intelligence world.

Microsoft Chairman and CEO Satya Nadella also tweeted that the major investor in OpenAI — behind the chatbot that kicked off the generative AI craze — looked “forward to getting to know” OpenAI’s new chief executive, former Twitch leader Emmett Shear, and the rest of the management team.

Nadella wrote on X, formerly known as Twitter, that Microsoft was “extremely excited to share the news that Sam Altman and Greg Brockman, together with colleagues, will be joining Microsoft to lead a new advanced AI research team.”

Altman said “the mission continues,” in reply to Nadella on X.

OpenAI said Friday that Altman was pushed out after a review found he was “not consistently candid in his communications” with the board of directors, which had lost confidence in his ability to lead OpenAI.

Altman catapulted ChatGPT to global fame while serving as company CEO and in the past year has become Silicon Valley’s sought-after voice on the promise and potential dangers of artificial intelligence.

OpenAI last week had announced co-founder Brockman would step down as board chairman but remain onas president. Brockman followed with a post on X reprinting a message he sent to OpenAI employees in which he wrote, “based on today’s news, i quit.”

In another X post Friday night, Brockman said Altman was asked to join a video meeting with the company’s board members, when co-founder and chief scientist Ilya Sutskever informed Altman he was being fired.

Brockman added that he was informed of his removal from the board in a separate call with Sutskever a short time later.

“Sam and I are shocked and saddened by what the board did today,” Brockman wrote on X.