The 47-year-old actor - who has played the camp swashbuckling hero in four instalments of the film franchise - feels he is "completely different" to the role, but adds he cannot shake him off.
He said: "In terms of any connections to the character of Captain Jack, we are completely different, there is nothing I can relate to Captain Jack whatsoever.
"With every character you play, there is a part of you which goes, in terms of ingredients of making this stew, so there is most definitely a part of me in Captain Jack and now, fortunately or unfortunately, there is a great part of Captain Jack In Me as well.
"Basically I can't shake him, he won't leave me alone! He keeps showing up at odd times, in fact he arrived this morning when I was getting my kids ready for school. I had to shoo him away."
Despite the lack of connection, Johnny does feel he could carry on playing the part infinitely because there are "limitless" possibilities as to where he could go.
He told The Independent newspaper: "Interesting for me, a character like Captain Jack, you feel like you can just continue.
"The possibilities are endless and limitless. There is any possibility of Madness and absurdity so, you feel like with the character, you're never really done."