Bradley Manning, the US soldier sentenced to 35 years for leaking secret documents, says she now considers herself a woman called Chelsea.
"As I transition into this next phase of my life, I want everyone to know the real me," the 25-year-old said in a statement read out on NBC's TODAY show in the presence of her lawyer, David Coombs on Thursday.
"I am Chelsea Manning, I am a female."
"Given the way I feel and have felt since childhood, I want to begin hormone therapy as soon as possible," the statement said.
"I also request that starting today you refer to me by my new name and use the feminine pronoun."
On Wednesday, a military court sentenced Manning to 35 years in jail for handing secret government documents to WikiLeaks, resulting in America's biggest-ever security breach.
Manning will serve her sentence in military custody before being dishonourably discharged.
She has spent most of her detention at Fort Leavenworth military base in Kansas where she was expected to serve her time.
After the announcement, Mr Coombs told NBC Manning has not indicated whether she would be pursuing sex change surgery.
"I don't know about the sex reassignment surgery ... Chelsea hasn't indicated that that would be her desire, but as far as the hormone therapy, yes," he said.
"I'm hoping Fort Leavenworth would do the right thing and provide that."
Mr Coombs added: "I think the ultimate goal is to be comfortable in her skin and to be the person that she's never had the opportunity to be."