A source close to the couple spilled the beans and said West always wanted a daughter.
Kardashian, 34, has not officially confirmed her baby's gender but last month she revealed West's feelings about the pregnancy, reported Radar online.
"It is really cute how excited he is," a source said.
Few days ago, Kim had tweeted a picture of her baby niece Penelope, daughter of her sister Kourtney, and wrote, "Penelope is wearing the little Balenciaga bag I got her for Christmas."
The couple have been dating for almost a year.