Agree. David Bowie once demonstrated it to a reporter. They walked together through Manhattan. No one bothered them. Bowie then said he was going to “turn it on”. Something in his expression slightly changed. And then he was mobbed by fans.
https://www.sunnyskyz.com/blog/2610/No-One-Recognized-Marily...
https://psychcentral.com/blog/the-marilyn-monroe-effect-the-...
I wouldn't be surprised if this is a common trait of celebrities. Wear a mask, literally or figuratively, on stage or camera. Take the mask off and you're just an ordinary person that no one else will notice.
Bowie talked about that mask here, and how he used it to face his fears:
https://neil-gaiman.tumblr.com/post/166082106996/my-friend-t...
https://www.nytimes.com/2016/01/17/fashion/david-bowie-invis...
My local neighbourhood has its fair share of nationally known famous faces. I’ve never once seen any of them treated like a celebrity because they don’t act like one.