The controversial rapper made the life-changing announcement Sunday during a concert in Atlantic City, New Jersey.
He told the crowd of more than 5,000 at Revel Resort's Ovation Hall in song form: "Now you having my baby." West then asked concertgoers to congratulate his "baby mom".
Kim Kardashian has since confirmed the news.
It's true," the 32-year-old reality TV star said in a statement on her site Monday. "Kanye and I are expecting a baby. We feel so blessed and lucky and wish that in addition to both of our families, his mom and my dad could be here to celebrate this special time with us."
Several members of the Kardashian clan have since tweeted about the baby news.
"Im a happy girl !!!!!!!!! Wowza! Oh BABY BABY BABY!!" Kim's mom Kris Jenner tweeted.
"Keeping secrets is hard with so many family members! Especially when you are so freaking excited!!!!! Love is everything!!!!" Khloe Kardashian tweeted.
"Been wanting to shout from the rooftops with joy and now I can! Another angel to welcome to our family. Overwhelmed with excitement!" Kourtney Kardashian tweeted.
The rapper and Kim Kardashian went public with their relationship in March. The reality star's divorce to NBA player Kris Humphries is still not finalized.
Kim is reportedly about 12 weeks pregnant.
The Associated Press contributed to this report.