REmake costume room location?

Just beat remake, got the costume room key, but I don't know where the costume room is.

I know of two locations. Ones in the REmake and once in the original. First I can think of is behind the large portrait in the small room behind the movable shelf in the statue room. The second I can think of is a door in the back corner of the room in the large mirror room. I don't know which one belongs to the original or not. Haven't played them in a while.

This should be of help - 03:57.