Well, that's what you call a well-kept secret.

Cardi B is pregnant with her first child with Migos rapper Offset, but it turns out the pair are more than just partners. In fact, they got married last September and managed to keep it under wraps until now.

The 'Bodak Yellow' shared the news with a note on Twitter, revealing that their on-again-off-again relationship led to them waking up one morning in September and "deciding to get married".

"We found someone to marry us, and she did, just the two of us and my cousin," she wrote. "I said I do with no dress, no makeup and no ring!"

She ended the note saying: "Well now since you nosey lil fucks know at least ya can stop saying I had a baby out of wedlock" and captioned the post "This why i name my album “Invasion of privacy” cause people will do the most to be nosey about your life .Welp fuck it ."

Cardi B was due to play Dublin's Longitude festival next month, but pulled out of the gig after announcing her pregnancy. Migos, on the other hand, are set to play the same event.