Kim Kardashian accidentally revealed that she is having a baby girl on The Ellen Show.

The 37-year-old reality television star – who is already mother to North, four, and Saint, one – accidentally let slip the sex of her unborn child by surrogate to US talk show host Ellen DeGeneres.

Kardashian relayed the story of her baby shower she threw over the weekend, which she admitted was mainly for the benefit of her daughter North, when she revealed the news.

The cosmetics mogul said: "I thought I really do want to have a baby shower, because I want her to feel that something's coming, and for her to really understand it.

"So people brought toys and gifts, and she was opening them all up the next day and she said: "mom, you know since baby sister is not here, I think I need all of her toys in my room, and I'll play with them and make sure they are all okay for baby sister."

DeGeneres replied: "She's a toy tester... and you just told us it's a girl."

Kardashian didn't appear too miffed about letting the cat out of the bag, confirming that a little girl was on the way with a big smile. She also said that "North is really excited" at the prospect of having a baby sister.

The star opted for a pregnancy via surrogate with husband Kanye West this time around, following frightening complications with her second pregnancy.

The couple are also said to be struggling with a baby name for their third child, so DeGeneres offered a name suggesting game which failed to prove any contenders.

Kardashian has since shared a throwback snap of herself with husband of three years West on Instagram. The reality star looks ultra-glamorous in the snap which sees her in a big brown fur coat and oversized sunglasses, while the Famous hitmaker looked wrapped up in a big black coat.

She captioned the shot: "A few years ago".

One fan replied: "Mom and daddy! My favorite couple @kimkardashian", while another put: "Couple goals".

A few years ago

A post shared by Kim Kardashian West (@kimkardashian) on