Acting out of existence.

Actors, particularly famous ones, do a curious extra thing when acting.
The whole acting thing is quite odd. To my mind, very few actors are genuinely good. Even a huge percentage of those lauded as 'great's are mediocre and generally typecasted into greatness, in my opinion. Since I'm not a film buff, I don't think my limited pool of favourite A classers is much of a proof group. So I won't name names.
But, the extra special thing that they all do I think is verging on paradoxical. It's not, of course, if you think in depth about it, but then if you think in depth about the whole movie business, it's all a bit weird.
Kids stuff. Very, very expensive kids stuff.
But what they all do, to a lesser or greater degree depending on their famousness, is to act themselves out of existence. But it's not a thing they try to do, it's a bi-product.
When they are existing as the character they are playing, unless the character is themselves, that character is existing in a contemporary universe which does not feature themselves, the famous actor.
You don't get Robin Williams acting a fairly standardly naive, pleasant, kind hearted, teacher/little boy growing up too fast/robot, constantly having to fend off autograph hunters:

"Say!...aren't you Robin Williams?"
"Nope, I'm Jack"
"You are!...You were Mork...I loved that. What ever happened to Mindy?"
"I have no idea what you are talking about, contemporary human"


"Aren't you Tom Cruise?"
"Tom what?! Look...I'm a little busy here saving the world from tripods/being a bar tender/fighter pilot"


"...I am a survivor living in New York City. I am broadcasting on all AM frequencies. I will be at the South Street Seaport everyday at mid-day, when the sun is highest in the sky..."
"Hello?....hello?!...I got your mes....FUCK ME! Aren't you Will Smith?! Sign my tits!"


They can't exist, or the story would be ruined.
And the thing is that this is an invisibly sliding scale. Unknown actors would not reasonably expect to be autograph hunted or paparazzied. But as their fame profile expands, however, their ability to act themselves out of existence increases linearly, presumably with no extra effort required. I don't think it takes effort, because I'm not convinced that they don't know they don't exist in their movie.
"I'm not me...I'm someone else. I'm there somewhere."
They're not.

It's like how, very often, the people on Eastenders are watching something on TV, but it's never Eastenders.
Eastenders does not exist on Eastenders.

...or maybe they recognise it for the crock of shit it truly is.