Hough, who appeared on Monday night’s show, said he had just found out and was feeling OK.
A “breakthrough case” refers to someone who is fully vaccinated and contracts the virus.
In September, pro dancer Cheryl Burke shared that she had contracted a breakthrough case. A few days later, her dance partner on the show, Peloton fitness instructor Cody Rigsby, also tested positive.
Hough is not the first person on the show to test positive.
“Hey everyone I have some news to share and I wanted you to hear it straight from me,” he said in the video posted Tuesday. “Even though I’ve been fully vaccinated, I’ve just been diagnosed with a breakthrough case of Covid.”
“I feel strong,” he said. “I’m currently taking advice from medical professionals, doing everything I can to get better as fast as I can.”
The pair are currently in the finals with the show’s Season 30 finale set to air on November 22.
CNN has reached out for comment from ABC in regards to how Hough’s diagnosis will affect the finale.
He announced on his Instagram that his shows for his Vegas residency at The Venetian which had been scheduled for this week “will be rescheduled for a date soon.”