Citing unnamed sources close to the pair, People magazine reported the apparent breakup Friday.
Representatives for Hough, 24, and Seacrest, 38, declined to comment to ABC News about the reported split.
Hough Saturday tweeted a photo of herself with friends, along with the hashtag, "friendsarethebesttherapy."
The pair reportedly dated for more than two years. Seacrest gushed about Hough two months ago to TV-host Chelsea Handler, calling his then-girlfriend "phenomenal" and "the best part of each day."
The source claimed their busy work schedules were challenging and that they've decided to live apart, People magazine reported.
In addition to being the longtime host of "American Idol," Seacrest also hosts a syndicated radio show and owns a television-production company that produces several popular programs, including "Keeping Up With the Kardashians" and "Shahs of Sunset."
Hough, the former "Dancing With the Stars" champion dance pro, has appeared in films including "Safe Haven" and "Rock of Ages." She also has a country-music career.
Hough has said it was tough to balance her growing career and her relationship with Seacrest, but said in an interview with Parade magazine that "at the end of the day, you have to find a balance with what's really important.
"I'm so lucky that I have a great relationship," she added in the February 2012 interview with Parade. "I'm very blessed and I don't take anything for granted. I think if you alienate people and just focus on your work, then it just becomes lonely and it's not fun anymore."