Bradley Manning, the US soldier who leaked secret US government documents to the Wikileaks website, has announced he wants to live as a woman.
"I am Chelsea Manning," Pte First Class Manning said in a statement to NBC's Today programme. "I am a female."
The 25-year-old said he had felt female since childhood, wanted at once to begin hormone therapy, and wished to be addressed as Chelsea.
Pte Manning faces 35 years in prison for crimes including espionage.
The soldier could be released on parole after at least seven years in jail, his civilian lawyer David Coombs has said.
Mr Coombs has asked President Barack Obama to pardon Pte Manning, and has pledged to appeal against the verdict and sentence.
Pte Manning will serve the sentence at Fort Leavenworth, Kansas, and on Thursday, Mr Coombs indicated the soldier was willing to take legal action to force the prison to provide hormone therapy if authorities refused.
He said Pte Manning had not indicated whether he wanted to undergo sex reassignment surgery.
"The ultimate goal is to be comfortable in her skin and to be the person that she's never had an opportunity to be," he said.
Asked why Pte Manning was making this announcement now, the day after sentencing, Mr Coombs said: "Chelsea didn't want to have this be something that overshadowed the case."
Pte Manning's struggles with gender identity formed a key part of the defence through the weeks-long court martial.
Defence witnesses, including therapists who had treated Pte Manning, testified that the soldier had spoken of wanting to transition to being a woman, suggesting that these problems had affected his mental health.
Wig and lipstick
Pte Manning's former Army supervisor testified that the accused had sent him a photograph of himself wearing a blond wig and lipstick.
US military prosecutors, meanwhile, described Pte Manning as a notoriety-seeking traitor and asked for a 60-year sentence in order to deter future intelligence leakers.
Pte Manning, who grew up in the US state of Oklahoma and in Wales, joined the Army in 2007 to help pay for university and, according to court martial defence testimony, to shake off a desire to become a woman. The soldier trained as an intelligence analyst and was deployed to Iraq in 2009.
There, Pte Manning became disillusioned with the war and felt increasingly isolated from friends and family.
In May of that year, Pte Manning initiated what subsequently became one of the largest leaks of classified US government documents ever - hundreds of thousands of diplomatic cables and battlefield reports from Afghanistan and Iraq.