Noam Shazeer, Vice President of Engineering and Gemini co-lead at Google DeepMind, announced Wednesday he is leaving to join OpenAI. Sharing the news on X, Shazeer wrote, “I’m excited to share that I’ll be joining OpenAI and look forward to working with the exceptional team there.” Responding to Shazeer’s post, OpenAI CEO Sam Altman called him “one of the people I have most wanted to work with since the very beginning of OpenAI,” adding the partnership was “only 10 years” in the making. Shazeer is best known as a co-author of the landmark 2017 paper “Attention Is All You Need.” His trajectory spans over two decades at Google, a stint as CEO of AI character maker Character.AI and a return to lead Gemini development. After leaving Google in 2021, he co-founded Character.AI, which later signed a licensing deal with Alphabet Inc. in August 2024. Under that agreement, Shazeer and co-founder Daniel De Freitas rejoined Google DeepMind, where he rose to VP of Engineering and Gemini co-lead. Shazeer‘s departure comes just weeks after Alphabet introduced new AI products, including the Gemini 3.5 Flash model and the Gemini Spark AI agent, at its annual I/O developer conference.