Shania Twain is engaged to Frederic Thiebaud, an executive with Nestlé, the Swiss-based food and beverage corporation. A spokesman for the singer-songwriter confirmed the engagement Monday (Dec. 20) to CMT Insider. It was announced by Us magazine, and additional details of the couple's relationship and engagement will be featured in a cover story in the magazine's issue which hits newsstands Tuesday. In August 2009, Twain confirmed she was dating Thiebaud after her divorce from record producer Robert "Mutt" Lange, who allegedly had an affair with Thiebaud's wife, Marie-Anne Thiebaud. Media reports indicated the singer had been a close friend of Marie-Anne Thiebaud, who managed Twain and Lange's chateau in Switzerland. Twain and Lange were married 14 years and have a 9-year-old son, Eja. Although Twain's spokesman declined to offer additional details on the engagement, People magazine reports that Thiebaud, 40, presented Twain, 45, with a three-carat solitaire diamond ring. Twain's autobiography will be published this spring by Atria Books. She will also be featured in an upcoming series on Oprah