The singer, 50, confirmed her pregnancy to People magazine with an exclusive photo showing off her baby bump.
"We thank God for our blessing," Jackson told the magazine.
The singer announced in April that she was postponing the second leg of her "Unbreakable" world tour indefinitely because she and her husband, Qatari business magnate Wissam Al Mana, were "planning our family."
"I have to rest up, doctor's orders," she told fans in a video posted on Twitter.
Since then, the star has kept a low profile, although she was photographed last month while furniture shopping in London.