JAY-Z finally reveals the story behind the twins' names

Another great life mystery solved!

And solved thanks to JAY-Z, who at long last explained the meanings behind the names of his and Beyoncé's twins Rumi and Sir, who were born in June.

While we've heard rumors from grandma Tina Knowles Lawson, Beyoncé's mother, it's best to get it from the horse's mouth. So what's up with calling your kids Rumi and Sir, anyway?

Well, as JAY-Z explained on Rap Radar podcast on Friday, we pretty much got it right that Rumi is named after the 13th Century poet Jalāl ad-Dīn Muhammad Rūmī, but the 'Sir' part needed a little explaining.

"Sir was like, man, come out of the gate," said the proud papa. "He carries himself like that. He just came out, like, 'Sir!'"

Lester Cohen / Getty Images for NARAS
Jay-Z with daughter Blue Ivy Carter at the 59th Grammy Awards in February in Los Angeles.

Beyoncé, who started her career in the girl group Destiny's Child, and rapper/entrepreneur JAY-Z have been married since 2008; their first child, Blue Ivy, was born in 2012. And he spoke about her a little, too, since she's already getting an early start on her own music career, having rapped on dad's new album "4:44."

As he noted, she just got up on a stool and started rapping. "I was like, 'Oh, s---!'" he recalled. "I have [her full freestyle] on my phone. Five minutes of her doing that!"

Clearly, these kids are born for great things.

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