New Delhi, April 29 -- Elon Musk, the Tesla CEO, world's richest man and OpenAI cofounder, took the stand Tuesday in a high-stakes trial revolving around a bitter feud with his former friend Sam Altman that could reshape the future development of artificial intelligence.

His testimony at the Oakland, California, federal courthouse kicked off a legal drama that is expected to brim with intrigue and potentially embarrassing details about the two tech moguls. Musk filed the lawsuit against Altman and his top lieutenant, Greg Brockman, along with Microsoft over its investments in OpenAI, in 2024.

"Fundamentally, I think they're going to try to make this lawsuit . very complicated, but it's actually very simple," Musk said. "Which is that it...