Shawn "Jay Z" Carter poses with his mother Gloria Carter at a fundraising event to support his college scholarship program in New York. Picture: AP

Jay-Z has admitted he "really cried" when his mother Gloria Carter came out to him, as he was "so happy for her".

The 48-year-old rapper's mother Gloria Carter revealed she identifies as a lesbian when she duetted with her son on his track 'Smile' - which appeared on his latest album '4:44' - in which the pair celebrate her sexuality, and reveal what it was like to keep quiet for the sake of Gloria's brood.

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And now Jay-Z has opened up on the emotional heart-to-heart the pair had when his mother told him her secret, admitting he is happy she can now be "free".

Speaking during an appearance on David Letterman's Netflix talk show 'My Next Guest Needs No Introduction', Jay-Z said: "Imagine having to live your life as someone else and you think you're protecting your kids. 

And for my mother to have to live as someone that she wasn't and hide and protect her kids ... [she] didn't want to embarrass her kids for all this time. And for her to sit in front of me and say, 'I think I love someone...' I mean, I really cried. That's a real story.

"I cried because I was so happy for her that she was free. This happened eight months ago when the album was being made. She told me. I made the song the next day."

In their duet, Jay-Z - who has six-year-old daughter Blue Ivy, and nine-month-old twins Rumi and Sir with his wife Beyonce - reveals his mother's sexuality, and praises her for being strong.

He raps: "Mama had four kids, but she's a lesbian/ Had to pretend so long that she's a thespian/ Had to hide in the closet, so she medicate/ Society shame and the pain was too much to take."

And later adds: "Don't matter to me if it's a him or her/ I just wanna see you smile through all the hate/ Marie Antoinette, baby, let 'em eat cake."

Last September, Gloria revealed during an interview that Jay - whose real name is Shawn Carter - had begun "tearing up" when she told him about her sexuality.

She said: "I just finally started telling Jay who I was. Besides your mother, this is the person that I am. This is the life that I live. So my son started actually tearing. He's like, 'That had to be a horrible life, Ma.' I was like, my life was never horrible. It was just different, so that made him want to do a song about it. The first time I heard the song I was like, 'Eh, I don't know dude. I ain't feeling that.'"