After months of testing, it seems Google is rolling out a button for AI Mode directly in the search box on Google's home page - on Google.com. This seems like a big deal to me, and goes along with AI Mode being the first tab in the main search results.
I covered this on Friday at Search Engine Land after noticing it come up on both Chrome on Mac and PC both signed in and out; Safari and Microsoft Edge.
Here is what it looks like:
Here is a static image:
Here is what it looked like before:
Hat tip to @swetav07 for making me look again at this.
Forum discussion at X.