The beauty entrepreneur shared a video to Instagram confirming the news, after weeks of speculation.
The 90-second video shows many personal moments from her pregnancy journey so far, including her positive test, the moment she told Scott, the family on the way to the doctor for their first scan with daughter Stormi, 3, in tow, and them sharing the news with Jenner’s mother, Kris Jenner.
“Stormi, we are going to have a baby,” Kris says to her granddaughter as she is handed scan photos. “This is one of the happiest days of my life.”
The video also includes footage from Jenner’s recent 24th birthday party, which she kept largely off social media.
It ends with an adorable moment showing Stormi kiss her mother’s stomach, as she says “baby”.
The video, also shared by Scott on his Instagram Stories, has delighted fans. Jenner, who is an avid social media user, chose to keep her first pregnancy off social media completely, only confirming the news once Stormi was born in February 2018.
However, it seems Jenner will be sharing much more of her pregnancy journey the second time around.
The video, which has been viewed more than 30 million times in the four hours since it was posted, has attracted plenty of well wishes from the couple's A-list friends.
“My heart is bursting for you,” wrote model Gigi Hadid. “Congratulations.”
Her sister, Bella Hadid, wrote: “I can’t, so beautiful. Bawling, best mama. So happy for you.”
Jenner’s famous sisters also sent their congratulations via Instagram. “This is so beautiful my blessed angel sister,” wrote Kourtney Kardashian.
While Kim Kardashian simply said: “Crying.”
While this is the first time Jenner or Scott has confirmed the news, rumours had been circulating online over the past few weeks that the couple were expecting, after Caitlyn Jenner, Kylie’s father, was filmed telling members of the public that she had just found out her 19th grandchild was “in the oven” as she toured the damage caused by Dixie Fire in California.