The 24-year-old reality star and makeup mogul revealed the news by posting a video to her verified Instagram account, where she shared images of the early stages of her pregnancy.
Jenner shows a positive pregnancy test to Scott, who then hugs her belly.
In another scene, Jenner reveals the news of her pregnancy to mother Kris Jenner, who opens an envelope handed to her by Stormi that contains ultrasound images.
“What is it, are you pregnant?” Jenner’s mother asks her.
“Stormi, we’re having a baby,” she adds. “This is one of the happiest days of my life.”
The video ends with a vignette of Stormi kissing Jenner’s baby belly.
Members of the Kardashian-Jenner clan congratulated the couple in the video’s commentary section, with sister and model Kendall Jenner saying, “I can’t take it.”
“Cry!!!!” Kim Kardashian wrote.
“This crying is so beautiful my blessed angel sister,” wrote Kourtney Kardashian.
“Awwww,” Khloe Kardashian said.
She has not disclosed further details about her second pregnancy.