Pregnant Jenna Johnson Mourns Death of 'Beautiful' Baby Niece Lennon: 'Unimaginable'

Phillip Faraone/Variety via Getty; Jenna Johnson/Instagram

Jenna Johnson is mourning the loss of her baby niece Lennon Sky, who was delivered stillborn last week.

On Wednesday, the Dancing with the Stars pro, 28, announced on Instagram that her brother Ashton Johnson and his wife Skyler "went through the unimaginable as they lost their baby girl this last week."

Jenna shared a series of photos from a snowy graveside memorial for Lennon, where a photo of the baby girl was on display and a bouquet of flowers was placed on top of her small casket.

"I've been in awe at their examples of hope and immeasurable strength during this heart wrenching time," wrote Jenna, who is currently pregnant with her first baby with husband Val Chmerkovskiy.

"So grateful for forever families and that our whole family was able to be together in honor of our beautiful niece, Lennon Sky Johnson. 💗," she continued. "Please send Skyler and Ashton all of the love and prayers 🫶🏼."

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Ashton and Skyler also opened up about the death of their daughter in a joint Instagram post on Wednesday, noting that their "sweet little angel girl was stillborn" on Dec. 2.

"We're so grateful we got to meet her & snuggle her precious body. We love our Lenny girl so much & have felt her presence daily," they wrote. "We know that she will always be with us, watching over us, & comforting us throughout our life 👼🏻 #familiesareforever."

In July, Johnson and Chmerkovskiyexclusively revealed to PEOPLE that they are expecting their first child together.

At 20 weeks pregnant, they announced on Instagram that they're expecting a baby boy. The couple used confetti cannons to reveal the sex of their little one, posting a series of photos of them shooting off blue confetti.

"Today we are officially halfway there to meeting our son," Johnson captioned the photos.