Why, often in film credits, are the actor’s and character’s name often written as, for example, “Ian McKellen – Gandalf (as Ian McKellen)”, but only for certain cast members?

Question

I’ve seen this a lot on IMDB, and this was just an example using more well-known names. For a direct example, I was looking up the cast for the 1999 film, DragonHeart: A New Beginning, and the lead actor, Chris Masterson, is listed as “Christopher Masterson – Geoff (as Christopher Masterson)”, and another character is ” Vladimir ‘Furdo’ Furdik – Sentry (as Vladimir Furdik)”, but only those 2 actors were listed that way. What does it mean that their character is “as the actor”, but it’s only true for them and not anyone else in the cast?

In: 80

Answer 1

Generally these are for actors who have been officially credited under different names.

E.g., Ian McKellen is usually credited as “Ian McKellen” but other times as “Sir Ian McKellen”.

Chris Masterson has been officially credited as “Chris Masterson”, “Christopher Masterson”, and “Christopher Kennedy Masterson” in the past.