Kim Kardashian reveals sex of baby on 'Ellen'

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Kim Kardashian and Kanye West will welcome a baby girl some time early next year.

The 37-year-old “Keeping Up With the Kardashians” star revealed the baby’s gender on “The Ellen DeGeneres Show” Wednesday.

>> Related: Report: Kim Kardashian, Kanye West to welcome baby in January

Kardashian let the news slip while talking about a baby shower she hosted this past weekend.

“My daughter (North West) thinks she’s really tricky. We had a baby shower over the weekend. I thought, ‘I really do want to have a baby shower because I want (North) to feel that something’s coming and for her to really understand it,” Kardashian told DeGeneres. “People brought toys and gifts. She was opening them all up the next day and she said, ‘Mom, Baby Sister’s not here. I think I need all of her toys in my room. I’ll play with them and just make sure they’re OK for Baby Sister.’”

"You just told us it's a girl," DeGeneres replied.

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According to Kardashian, 4-year-old North is excited to welcome her sister. But 1-year-old Saint West doesn't have an understanding of the pregnancy, especially since his mother doesn't have the pregnant belly.

“I don’t know if my son gets it yet, especially since I don’t have the belly. It is a different experience. I said to my sisters, ‘Would it be really creepy if I just had someone dress up like a big stork and drop the baby off at the front door?’” Kardashian said.

Kardashian and West announced in September that they would be having a third child via surrogate. The couple has not yet chosen a name for their new bundle of joy.

Kim Kardashian attends Harper's BAZAAR Celebration of "ICONS By Carine Roitfeld" at The Plaza Hotel presented by Infor, Laura Mercier, Stella Artois, FUJIFILM and SWAROVSKI on in NYC. (Dimitrios Kambouris/Getty Images for Harper's BAZAAR)