The Washington Post reported the 73-year-old singer went to the U.S. embassy in Bern Oct. 24 to complete the Statement of Voluntary Relinquishment of U.S. Citizenship paperwork, in which she stated she no longer has any links to the United States "except for family, and has no plans to reside in the United States in the future."
She took the oath of Swiss nationality April 10, the Post said.
Turner married German music producer Erwin Bach, her boyfriend of 27 years, last summer.
Notable deaths of 2014 [PHOTOS]
S Club 7 to reunite for BBC charity event