The TV personality took to Instagram Thursday, where she confirmed she'll be missing out on filming the new live episode of "Big Brother" ... as she's been diagnosed with COVID-19.

Per the announcement, Chen first began feeling under the weather on Friday last week and decided to visit her good friend, who happens to be a doctor. The "Big Brother" host shared this is the second time she's been diagnosed with the disease, but noted her symptoms were "very mild" ... just a sore throat this time around.

While Chen said she was feeling better days after her diagnosis, she was still testing positive ... making it impossible for her to return to set.

She continued ... "Thank you to Jerry O'Connell for filling in for me. I hope Jerry fits in to my dress, has a ball and tells the houseguests I miss them but will be watching from home."

Poking fun at her "Chenbot" reputation, Julie joked her case of COVID proves she's "human after all!"

Countless fans and famous friends have already sent Chen their well wishes, including Andy Cohen and Carson Kressley, among others.

Some wondered if this was the first time JC had ever missed a live show ... with many noting they couldn't recall a single instance.

Jerry O'Connell also commented on his last-minute hosting gig, calling Chen on "The Talk" to get some advice ahead of the big evening.