Microsoft boss Satya Nadella officially declared war on Google saying that the race between the pair started today..
Developed by Microsoft-backed OpenAI, ChatGPT uses deep learning techniques to generate human-like responses to search requests.
Nadella said he thought ChatGPT was poised to change the nature of online search - and interactions with many other software.
"This technology will reshape pretty much every software category that we know," he said.
Bing will now respond to search queries with more detailed answers - not just links to websites.
Users can chat with the bot to better tailor their queries. More contextual answers will be added on the right hand side of a search page.
The new Bing search engine will be live right away - with a limited number of searches for each person.
In a note to investors after the announcement, analyst Dan Ives of Wedbush Securities said he thought that Microsoft's investment would "massively boost" the firm's ability to compete.
"This is just the first step on the AI front ... as [the] AI arms race takes place among Big Tech," he said.
ChatGPT has been criticised for confidently giving answers that are wrong. It also works on datasets that are generally scraped from 2021 which does not help either.