Pregnant Kylie Jenner Covers Up as She Poses With Sisters in Underwear Ads

The Kardashian-Jenner women are all featured in Calvin Klein's latest underwear campaign.

Kylie Jenner is doing everything she can to cover up her baby bump -- even when posing in undergarments.

The 20-year-old reality star joins sisters Kourtney, Kim and Khloe Kardashian as well as Kendall Jenner in the latest Calvin Klein underwear and jeans ads, and manages to not show too much skin. 

ET has learned that the photo shoot took place in October, not long after we confirmed that Kylie is expecting.

Calvin Klein/Willy Vanderperre
Calvin Klein/Willy Vanderperre
Calvin Klein/Willy Vanderperre

In one of the images -- taken by photographer Willy Vanderperre -- the siblings are all laid out on a big red-and-white quilt, and while her siblings are posing in their CK underwear, Kylie has the blanket draped over her, revealing only her bra. 

Khloe -- who, like Kylie, is pregnant with her first child -- also attempts to mask her stomach by placing a hand over her abdomen. 

After the release of the ads on Monday, momager Kris Jenner shared one of the photos on Instagram and declared that she was a "#ProudMama." 

"OUR FAMILY," she wrote. "Close like no other."

Calvin Klein/Willy Vanderperre
Calvin Klein/Willy Vanderperre

Kim further praised the campaign, tweeting: "Nothing better than working with my family! Honored to be shot alongside my sisters for the new CALVIN KLEIN UNDERWEAR and CALVIN KLEIN JEANS global campaign. Thank you @calvinklein - Our Family." 

Calvin Klein/Willy Vanderperre

Meanwhile, in a video ad for the brand, the sisters are seen lounging on the same blanket while playing a game of "Never Have I Ever."

"Never have I ever got a tattoo," Kim shares.

"Never have I ever dyed my hair," Kendall admits.

Kourtney chimes in, "Never have I ever jumped out of a plane."

It's Kylie's turn next, who confides, "Never have I ever eaten a rattle snake." Kourtney notes, "I have."

"Never have I ever been married," Kendall adds. "Same," Kourtney responds before pounding fists with her supermodel sister.

While Kylie joins her family for these CK ads, she was noticeably absent from the Kardashian-Jenner Christmas card in December. 

A source close to the famouos family told ET last week that Kylie has "been taking time out of the spotlight to prepare for her new life as a mother."

The source also noted that the youngest Jenner sister is "excited to be a mother," adding, "She knows she has the best teachers to guide her through being a great mother, her own mother and sisters."