Bristowe, 35, announced the news on Instagram on Thursday alongside a photo of herself and Tartick sitting in front of a Christmas tree, looking less than thrilled.
“Unfortunately, this is our Christmas card this year,” she began in the caption. “We have Covid.”
The reality star said that she and her beau thought they “were making a responsible decision to have ONE person over” to their home after quarantining. She said their guest is tested daily for work and had tested negative several times.
“The day we saw her, she became positive which we all found out the next day,” said Bristowe. “Now, like many, we will spend Christmas by ourselves.”
She continued: “We just want to let everyone know that we thought we were being safe, but covid is bigger than us.”
The star concluded her post by sending well wishes to “anyone who is sick or overcoming something,” as well as to “healthcare workers who have been away from family, taking care of others for months, and months now.”
“We will be ok!!” she assured. “Be safe and happy holidays!!”
Tartick shared a video to his own Instagram in which he recalled their “Christmas story,” and the quarantine plan they believed to be a “responsible” one, which was rattled by contracting the virus.
He said they’ve come down with symptoms such as a fever, achiness and a cool sweat when sleeping.
“You just can never be too cautious and careful,” he said in the caption, in part. “There’s no outthinking this god awful virus, lesson learned. Thoughts and prayers are with all of those who have been impacted by Covid, to those who have endured a challenging 2020, to the healthcare workers putting their lives on the line everyday for others and to those who are family less during the holiday.”