Updated

Kim Kardashian and Kanye West announced the name of their baby girl on Friday.

Kardashian posted their daughter's name on Twitter with a simple tweet that read, "Chicago West."

While the celebrity couple did not offer an explanation for the unique name, Kanye West grew up in the Windy City.

Chicago joins the couple's daughter North, 4, and son Saint, 2.

West and Kardashian welcomed Chicago via surrogate on Monday.

"Kanye and I are happy to announce the arrival of our healthy, beautiful baby girl," Kardashian said on her app on Tuesday. "We are incredibly grateful to our surrogate who made our dreams come true with the greatest gift one could give and to our wonderful doctors and nurses for their special care. North and Saint are especially thrilled to welcome their baby sister."

The reality star celebrated the birth of her daughter by wearing her birthday suit. Kardashian shared an image of herself lying in bed sans clothing on Friday before announcing her newborn's name.

Kardashian shared the racy image with her 106 million Instagram followers.

According to People magazine, the image was snapped by fashion photographers Mert and Marcus.