US rap star Cardi B has welcomed her fourth child - her first with American footballer Stefon Diggs.

The Grammy winner shared news of the baby boy's arrival on Instagram, writing: "I brought new music and a new album to the world! A new baby into my world, and one more reason to be the best version of me, one more reason to love me more than anything else or anyone else."

Last month, Cardi B released her long-awaited sophomore album - Am I The Drama? - issuing a public plea for people to buy it so she can afford nappies.

The hip hop superstar - real name Belcalis Almánzar - shares three children with her estranged husband Offset. She filed for divorce from the Migos rapper in July 2024.

Representatives for Cardi B did not immediately respond on Friday to the BBC's requests for comment. 

Cardi B did not share details about the child's birth, but her spokesperson told People magazine on Thursday that Cardi had a baby boy and is "healthy and happy". 

Diggs, whom the rapper has been dating for about a year, revealed the child's sex during a red-carpet event earlier this month.

"It's a boy. That's enough for me," the New England Patriots wide receiver told People at the time. "I can't wait to make him do push-ups and sit-ups and run around."

This is the second child for Diggs, who has a 9-year-old daughter from a previous relationship.

Sharing a clip from her single Hello on Instagram, the 33-year-old alluded to starting over after her last chapter. Presumably, that chapter includes her contentious break-up with Offset, with whom she shares daughters Kulture and Blossom, and son Wave.

She said that being a better version of herself allows her to "continue giving my babies the love and life they deserve". 

"This next chapter is Me vs. Me! It's me against all odds me against everything meant to get in my way," she wrote. 

She told her 163m followers that she is starting to prepare for a tour that corresponds to her new album, as well as getting her mind and body into shape to give her fans the "performance of a lifetime". 

"I've learned i've healed, and im loving the woman i've become! Thats what this next era means to me and i'm stepping into it better than ever," she wrote.