Jay Z has admitted his marriage ''wasn't totally built on 100 per cent truth''.

The 47-year-old rapper - who tied the knot to Beyonce Knowles nine years ago - admitted the ''hardest thing'' he's ever done is having to face up to potential difficulties in his union and try to work them out.

He said: ''This is my real life. I just ran into this place and we built this big, beautiful mansion of a relationship that wasn't totally built on the 100 per cent truth and it starts cracking. Things start happening that the public can see.

''Then we had to get to a point of, 'OK, tear this down and let's start from the beginning ... It's the hardest thing I've ever done.''

Jay - who has daughter Blue, five, and newborn twins believed to be named Rumi and Sir with his singer spouse - insisted his relationship had been more testing than when he was being shot at during his tough upbringing in Brooklyn, New York, and recalled one holiday where he begged her to stay.

He said: ''I was on a boat, and I had the best time. I was like, 'Man, this is great.' Then she had to leave. I was, like, crushed. 'Man, I don't even feel like this.

''What is happening to my body right now? I don't even feel like this. Did I just say... Don't leave?' ''

The '4:44' hitmaker admitted the couple's relationship has been ''uncomfortable'' at times due to being in the public eye, but insists the key to their union is honesty.

Speaking in a video 'Footnotes for '4:44'' to go alongside his latest album of the same name, said: ''We've been in that space where we just got to the place that in order for this to work, it can't be fake - not once.

''I'm not saying it wasn't uncomfortable because obviously it was, but because we've been doing it for so long it was less uncomfortable.''

The video, which was released on Tidal, also features conversations with several stars, including Will Smith, Kendrick Lamar, Chris Rock and Jesse Williams.

Jay's '4:44' title track features an apology from him to Beyonce, and speculation is rife that it is a direct reference to claims she hinted to him being unfaithful with ''Becky with the good hair'' on her visual LP 'Lemonade'.

His lyrics include: ''If my children knew, I don't even know what I would do. If they ain't look at me the same, I would probably die with all the shame.

''You did what with who? What good is a ménage a trois when you have a soulmate, you risked that for Blue?

''I apologise, often womanise, took my child to be born, see through a woman's eyes.

''Took for these natural twins to believe in miracles. Took me too long for this song. I don't deserve you.''

In another song he also appears to reference the infamous Met Gala 2014 incident in which he was attacked in a lift by sister-in-law Solange Knowles.

He raps: ''You egged Solange on, knowing all along all you had to say you was wrong.''