"The test will be for logged-in adult users on the Free and Go subscription tiers" in the United States, OpenAI said Monday. The Go subscription costs $8 in the United States.

Only a small percentage of its nearly one billion users pay for its premium subscription services, which will remain ad-free.

"Ads do not influence the answers ChatGPT gives you, and we keep your conversations with ChatGPT private from advertisers," the company said.

Since ChatGPT's launch in 2022, OpenAI's valuation has soared to $500 billion in funding rounds -- higher than any other private company. Some analysts expect it could go public with a trillion-dollar valuation.

But the ChatGPT maker burns through cash at a furious rate, mostly on the powerful computing required to deliver its services.

Its chief executive Sam Altman had long expressed his dislike for advertising, citing concerns that it could create distrust about ChatGPT's content.

His about-face garnered a jab from its rival Anthropic over the weekend, which made its advertising debut at the Super Bowl championship with commercials saying its Claude chatbot would stay ad-free.

In one spot, a man asking an AI chatbot for advice on communicating with his mother receives earnest guidance before the conversation veers into a pitch for a fictional cougar-dating site called "Golden Encounters".