Kim Kardashian West. Picture: Bang Showbiz

Kim Kardashian West is so pleased she got to "return the favour" of holding her sister Khloe Kardashian's legs up while she delivered her daughter on Thursday.

The 'Keeping Up with the Kardashians' star was by her younger sibling's side when she delivered her baby girl in the early hours of Thursday morning at the Cleveland Clinic in Ohio and Kim couldn't wait to gush about how "easy" she made it look. 

Taking to her Twitter account on Friday, she said: "@khloekardashian I'm so happy for you! Your baby girl is so beautiful! You are so strong, you made that look so easy! I can't wait for our baby girls to grow up as best friends the way we are! I'm so happy I was able to return the favor of holding your leg while you pushed LOL (sic)"

And to show her sister how proud she was of her, the 37-year-old beauty sent her a lavish baby bundle worth $8,000 so that she had something nice to come home to.

According to TMZ, Kim - who has four-year-old daughter North, two-year-old son Saint and two-month-daughter Chicago with her husband Kanye West - sent Khloe a Noitte Fatata custom bassinet from baby boutique Petit Treso worth $5,000, a range of organic bath products costing $1,000 and blankets worth $1,500. 

Khloe, 33, was due to give birth to her baby girl at the end of the month, but she went into early labour due to the stress of her boyfriend Tristan Thompson's alleged cheating. 

Despite the drama, Khloe allowed NBA star Tristan - who also has 16-month-old son Prince Oliver from a previous relationship - into the delivery room.

A source said: "Khloe laboured yesterday at the hospital. Tristan was there for the birth. He has practice today, but will spend as much time at the hospital as possible."

Khloe's relationship hit the headlines earlier this week when a video of Tristan emerged online of him chatting with an unidentified woman at the PH-D lounge in New York City earlier this month, before seemingly leaning in for a kiss.