"They were married at sunset in Rincon, Puerto Rico, in front of 40 of their closest family and friends," Twain's rep told the magazine.
Shania Twain gets engaged to ex-best friend's former husband
Twain, 45, and Swiss-born Thiebaud, 40, confirmed their engagement last month. The couple began dating after Twain's former best friend Marie-Anne Thiebaud (to whom Frederic was married) allegedly had an affair with Twain's husband of 14 years, Robert "Mutt" Lange.
Lange abruptly left the singer in May 2008 and the two have a 9-year-old son together, Eja.
Twain confirmed that she and Thiebaud had become romantic in August 2009, when she wrote on her website that she had found "a dear friend and true gentleman ... We leaned on one another through the ups and downs, taking turns holding each other up. We've become stronger and closer through it all."
Twain, who appeared as a guest judge on American Idol last season, can next be seen in her upcoming reality series, Why Not? With Shania Twain, on Oprah Winfrey's just-launched OWN cable network.