Tesh told the New York Daily News he and Winfrey used to date while working in local news in Nashville, Tennessee.
"Oprah: A Biography," written by Kitty Kelley, claims that Tesh and Winfrey lived together for a short time in the 1970s.
The book also says Tesh abruptly ended the relationship when he could not handle being in an interracial relationship.
Tesh did not comment on why they broke up.
Kelley has written unauthorized biographies on celebrities, including Jackie Kennedy, Frank Sinatra and Nancy Reagan.
The Associated Press contributed to this report.