Bradley Manning's letter, entitled The Next Stage of My Life, was signed with a handwritten signature in the name of Chelsea Manning.
The letter was broadcast on NBC's Today show as Manning's lawyer revealed the soldier's desire to live life as a woman.
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The Republican presidential candidate said Mrs Clinton "doesn't know what she's doing" in her plans for Syria.
Court records show Len Wiseman filed divorce papers on Friday citing citing irreconcilable differences.
The 35-year-old singer could have faced up to 30 days in jail if he was charged with breaking election laws in his hometown.