"Diamonds" singer Rihanna and partner A$AP Rocky secretly welcomed a son on Aug. 3, TMZ reported.
They also share a 1-year-old son, RZA Athelston Mayers.
Rihanna revealed that she was pregnant by showing off her baby bump onstage while headlining the Super Bowl halftime show in February. Moments later, her ex, Chris Brown, seemingly congratulated her on Instagram.
"GO GIRL," he wrote alongside a red heart and praying-hands emojis.
Brown last May also congratulated Rihanna, 35, and A$AP Rocky, 34, on the birth of RZA. The couple first announced news of the pregnancy via a New York photo shoot showing Rihanna's pregnant belly.
"Congratulations," Brown wrote at the time on Instagram, according to Page Six. The post was accompanied by emojis of a red heart, a pregnant woman, and praying hands.
Rihanna and Brown began dating in 2007 but split two years later amid revelations that Brown had physically assaulted Rihanna. He later pleaded guilty to felony assault. Three years later they got back together, dating for several months before calling it quits.
Leading up to the birth of her second child, Rihanna launched a maternity line for her lingerie brand Savage X Fenty in August. She showed off the line of nursing bralettes in a series of photos showing her nursing and cradling RZA for Vogue Magazine.
"I want to remind people that you can still channel sexiness and feel good while being a parent," she said.
Rihanna hasn't disclosed plans for new music, but she mentioned to Apple Music earlier this year that her return to live performances has been shaped by her journey through motherhood.
"When you become a mom, there's something that just happens where you feel like you could take on the world, you could do anything," she said, according to The Los Angeles Times
"As scary as [the Super Bowl] was because I haven't been onstage in seven years, there's something exhilarating about the challenge of it all. And it's important ... for my son to see that."