The reported "other woman" in Shania Twain's separation from her husband was a close friend of the singer's, sources told People magazine.
"Their two families would vacation and spend holidays together," one source said. "Shania considered Marie-Anne one of her best friends."
Music producer Robert "Mutt" Lange's relationship with Marie-Anne Thiébaud, 37, a longtime secretary and house manager at Twain and Lange's estate in Switzerland, was behind the breakup, several sources familiar with the situation told People.
"Mutt and Marie-Anne left their spouses for each other and are still in a relationship," said one source, adding that the Swiss employee was a fixture in the household Twain, 42, and Lange, 59, shared with their son, 6-year-old Eja D’Angelo.
After the separation was announced, Lange told People that an affair was "absolutely not the reason [for the breakup]... It's literally just a growing apart, that's all." He also denied that he was in a relationship with Thiébaud, saying, "It's not true."
Whatever the reason, Twain "is devastated," a source told People. "This came out of left field."
Twain, who married Lange in 1993, is best known for her hits "Man! I Feel Like A Woman!" and "You're Still the One." Lange produced three of Twain's albums: 1995's "The Woman in Me," 1997's "Come on Over" and 2002's "Up!"