Saint West, Kim Kardashian West & North West. Picture: Instagram

Kim Kardashian West's son Saint is a "genius", as he's already able to spell complex words at just two years old.

The 37-year-old reality star has taken to social media to claim that her two-year-old son Saint - whom she has with her husband Kanye West - is wise beyond his years, as he's already able to spell complex words.

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Kim - who also has four-year-old daughter North, and a newborn baby girl who came into the world on Monday - tweeted:

The 'Keeping Up with the Kardashian' star's excitement over her son's spelling abilities comes after it was previously claimed she and Kanye, 40, would be giving "extra attention" to Saint and North in the wake of the birth of their third child - who was born via surrogate mother - so that they don't begin to feel left out.

This smile 😁😊

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

A source said: "Kim wants to make sure North and Saint have a lot of extra attention and feel included as well. It's a big deal for everyone to have a newborn in the family. 

"Kim and Kanye are at home with the baby. They are so happy. They have had some visitors, but mostly Kris [Jenner] and Kourtney [Kardashian] are helping out."

Meanwhile, Saint's feat comes after he was admitted to hospital at the start of this month, where he was treated for pneumonia, and Kim later confirmed her son was "all better" after having been treated for the illness, in which a person's lungs become inflamed. 

Taking to Twitter, Kim shared: "My precious baby boy is so strong! After spending three nights in the hospital & seeing my baby get multiple IV's and hooked up to oxygen machines, our end of year was challenging. Pneumonia is so scary. I just want to thanks every nurse & doctor out there who works so hard around the clock. We are so grateful for you all! He's home and all better. He's so resilient I'm sure he will still say the ambulance ride was cool! My strong Saint (sic)"