To forget one's self

To become unmindful of one's own personality; to be lost in thought.
To be entirely unselfish.
To be guilty of what is unworthy of one; to lose one's dignity, temper, or self-control.

See also: Forget, Forget, Forget

References in classic literature ?
To forget one's self, to surrender all personal feeling in the service of that fine art, is the only way for a seaman to the faithful discharge of his trust.