At face value, this might seem like the liar paradox. You might expect a narcissist to be deluded about his own abilities since the reflection is not the face. However, clinical narcissism (NPD) intersects with traits like low empathy, high charisma, superficial charm and supreme self-confidence - a cluster of traits which make persuasive liars. If you don't care that you abuse minds with lies, present well, and believe you will conquer all - unless someone presents a strong challenge - then you will more likely make a persuasive liar.
I couldn't say if this were true in your case. I don't know enough about you. There will be a bell curve of delusion, just as there is a bell curve of intelligence and criminality on the psychopathic spectrum. However, bell curves tell us what is more or less likely of a group.
You might expect actors to have high narcissism to begin with. Those who are high in narcissism will be drawn to professions where they are the centre of the universe, so the profession likely exerts a selection effect. However, there is something called acquired situational narcissism (ASN), a term made popular by the psychiatrist Dr Robert B. Millman, which holds that some narcissistic traits emerge from a hothouse habitat. The actor is surrounded by fans who adore them and few or no critics; tyrants or ideologues with yes-men, secret police and emergency powers. When you have that type of power and immunity to critics, then you are more vulnerable to confirmation bias, the belief you are more powerful and more moral than you are. If we trust the ASN theory, then a person whose ideas conflict with reality, whose communal narcissism leads him to believe he is an invulnerable moral paragon, can be as dangerous as a clinical narcissist when disabused of that belief.