Google's artificial intelligence assistant Gemini has just reached one billion monthly users, CEO Sundar Pichai said Tuesday, only a week after a major leadership shake-up in the tech giant's AI division.

"It's our fastest-growing product ever," and the 14th product to reach a billion users, Pichai posted on social media.

The milestone, which Google calculated based on how many people use the Gemini app across its ecosystem, gives the search giant a victory amid a major overhaul of its AI division.

Demis Hassabis, who won a Nobel Prize in chemistry, recently stepped back from the day-to-day management of Google DeepMind, the lab that designs the Gemini models. And several leading researchers left as well, including Jeff Dean, a central figure in the group's engineering efforts for nearly three decades.

Its new flagship model, Gemini 3.5 Pro, initially promised for June, still has not been released, while its rivals have launched several models which are considered more powerful, particularly for generating computer code, currently the most lucrative area in the sector.