Have a look here: Actors awarded British knighthoods.
A quick look at some of the older names turned up Sir Lewis Casson, knighted in 1945, and thus pre-Elizabeth II.
Interesting. Royals used to loathe actors. Or nobles did anyway. Maybe royals were above the petty conceits of the noble classes. 
That is frikking awesome.
Would you mind telling me what that is, so I can go find it from somebody who DOESN’T block it in my country? God I hate that.
Trawling through that list it turns out Henry Irving was the first actor to be knighted, by Victoria, in 1895.
The monarch doesn’t decide who gets honours, by and large. It is up to politicians.
The title is “Patrick Stewart Alphabet”. It’s one of the Season 5 DVDs’ special features.