Kylie Jenner congratulates sister Khloe Kardashian on birth of baby girl

Making it social media official! Kylie Jenner took to Snapchat on Thursday to be the first member of Khloe Kardashian’s family to flat-out congratulate the "Revenge Body" star on the birth of her baby girl.

Kylie, 20, posted a video from her car driving down the road. The pink filter read, “Kongrats, Khloe! It’s a girl!”

ET ONLY kylie_jenner_snapchat

 (Snapchat)

Khloe and Kylie were pregnant at the same time this year, with Kylie giving birth to her daughter, Stormi, in February. After months of staying silent about Kylie's pregnancy, Khloe shared a sweet pic of them together after the news broke, writing, "What a magical ride it's been! I'll miss you bumping along with me."

Khloe Kardashian to Head Back to Los Angeles as Soon as Baby Is 'Ready to Travel'

Earlier in the day, the 33-year-old reality star welcomed her first child in Cleveland, Ohio, with her boyfriend, Tristan Thompson, at the hospital for the delivery. It’s been a difficult week for the new mom, who has been dealing with the rumors that the 27-year-old NBA pro allegedly cheated on her. 

"After a very tumultuous few days for Khloe, she has made the decision to fly home to Los Angeles as soon as the baby is ready to travel," a source tells ET. "Right now, she realizes she needs her family around her and knows they are the people in her life that she will always love and trust."

Kris Jenner Says She's 'Blessed' After Khloe Kardashian Gives Birth to Ninth Grandchild

Momager Kris Jenner and sisters Kim Kardashian West and Kourtney Kardasahin also flew to Cleveland to be with Khloe and meet her little girl. Kris took to Instagram after the birth, sharing a funny video of Kendall Jenner saying, “Baby, baby, baby!” and captioning it, “BLESSED!!!”

Right now the future for Khloe and Tristan is unclear.

"Tristan and Khloe talked about marriage before the videos came to light, but that has been put on the back burner," the source says, adding that the "Revenge Body " star's family and friends believe she "deserves better."

Tristan Thompson Spotted at Ohio Hospital After Khloe Kardashian Gives Birth: Pic