Which celebrity hair transformation impressed you

Celebrities are always changing up their hair — new cuts, colors, or styles — and sometimes the change is minor, sometimes it completely transforms their look. Some transformations become iconic, while others feel like they miss the mark.

I’m curious: which celebrity hair transformation impressed you the most, and why?
Was it a bold color change, a haircut that totally suited their face, or a style that became a trend?

Also, did their change inspire any of your own hair experiments or ideas?