The 36-year-old made the announcement on Tuesday on his Instagram, telling his followers in a video: "I have some news to share and I wanted you to hear it straight from me. Even though I've been fully vaccinated, I have just been diagnosed with a breakthrough case of COVID. I just found out."
The dancer said he's feeling "OK" and "strong."
"I'm currently taking advice from medical professionals [and] doing everything I can to get better as fast as I can," he added. "I'm currently in quarantine, and I'll make sure I keep you guys all updated with what's going on."
Hough recently appeared on Monday's episode of "DWTS."
He said he was rescheduling his shows in Las Vegas which were set to take place this week and new dates will be announced soon.
The news comes as "DWTS" is set to air its season 30 finale in less than a week.
Hough is the second member of the "DWTS" cast to be diagnosed with the virus.
In September, contestant Cody Rigsby and his partner Cheryl Burke each also contracted breakthrough cases despite them both being vaccinated.
The pair has since recovered.
RELATED: 'DWTS' pro Cheryl Burke says she has COVID-19