In some closing credits, one (*) actor is listed with the name of her/his character in addition, in the form: [Actor name] as [Character name]
.
I always thought this is the case for actors playing characters that are disguised (e.g., in monster costumes), or for actors that only gave their motion capture/voice (e.g., for digitally created characters).
For example (not the best example, as it contains a "Featuring" in addition), in The Lord of the Rings: The Return of the King (see video, at 3:31):
Featuring
Andy Serkis
as Gollum
Ah, The Hobbit: An Unexpected Journey contains it without "Featuring" (see video, 1:25):
Andy Serkis
as Gollum
But then I saw The Hobbit: The Desolation of Smaug, and if I remember it correctly (couldn’t find the credits online), it read:
Orlando Bloom
as
Legolas
Now this refutes my theory. Orlando Bloom is not acting disguised nor is he a digital creation.
What is the reason for this?
(* Maybe there are credits where this applies to several actors, but I noticed it only for exactly one actor so far.)
(Note that the question Why do some actors in credits appear as - Character (As Actor) may look similar, but that one is about the IMDb.)