AsianFin -- OpenAI CEO Sam Altman revealed in a recent interview that his admiration for his former collaborator, Elon Musk, has waned over time.

Speaking with former Fox News anchor Tucker Carlson in an interview aired on YouTube Wednesday, Altman discussed his evolving perspective on Musk, with whom he co-founded OpenAI in 2015. Their professional relationship ended after Musk left OpenAI’s board in 2018.

“For a long time, I looked up to him as an incredible hero, a great jewel for humanity. I have different feelings now,” Altman said.

He added, “There are things about him that are incredible, and I’m grateful for a lot of things he’s done. But there are also traits I don’t admire.”

Requests for comment from representatives of both Altman and Musk were not returned by Business Insider.

Musk was an early financial backer of OpenAI, though the exact amount he contributed to the company, which developed ChatGPT, remains unclear.