Jay-Z is ''paranoid'' about not being a great dad.

The rapper, who has an 18-month-old daughter Blue Ivy with his wife of five years Beyoncé Knowles, has revealed he takes his role as a parent very seriously because his own father walked out on him when he was very young.

The 'Run This Town' hitmaker opened up about his fears to legendary producer Rick Rubin in an emotional new Samsung spots video, saying: ''My pop left when I was young, so he didn't teach me to be a man, nor how to raise a child or how to treat a woman. Of course my karma, the two things I need, I don't have. And I have a daughter. It's the paranoia of not being a great dad.''

Jay-Z also revealed he has penned a new song about his little girl called 'Jay-Z Blue' for his new album, 'Magna Carta Holy Grail', and still can't believe that she exists.

He explained: ''She's something that we both created. We still marvel at her.''

The 17-time Grammy Award winner also raps about fatherhood on his new track 'Heaven', which he explained is about ''toying with that idea of it being heaven or hell on earth, no matter what religion you are.''

He added: ''For me, my idea is, heaven is in your daughter's laughter. Hell could be if your child was missing for three minutes, you're in three minutes of hell.

''It's just not my belief that a just God would make you burn for eternity for free will that he gave you.''