Kim Kardashian and Kanye West attend an NBA game on December 25, 2012 in Los Angeles,

Kim Kardashian and Kanye West attend an NBA game on December 25, 2012 in Los Angeles,

Kanye West and Kim Kardashian are expecting their first child.

The rapper announced the news at a concert in Atlantic City on Sunday night.

He told the crowd of more than 5000 at the Ovation Hall at the Revel Resort in song form: "Now you having my baby."

Kardashian confirmed the news the following day on her website. "It's true," the 32-year-old reality TV star's statement reads. "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."

Kardashian's father, Robert Kardashian, died in 2003. West's mother, Donda West, died in 2007.

Kardashian added in the blog post that she was "looking forward to great new beginnings in 2013 and to starting a family".

According to reports Kim Kardashian is twelve weeks along in her pregnancy.

The couple have been dating since April 2012.

The tweets of congratulations have already started to pour in for the happy couple.

Kim's sister Khloé Kardashian Odom wrote, "Keeping secrets is hard with so many family members! Especially when you are so freaking excited!!!!! LOVE is everything!!!!"

Kourtney Kardashian wrote: "Another angel to welcome to our family. Overwhelmed with excitement!"

West told concertgoers to congratulate his "baby mum" and that this was the "most amazing thing".

The rapper and reality TV star went public with their relationship in March.

Kardashian married NBA player Kris Humphries in August 2011 and their divorce is not finalised.

with AAP