Osama Bin Laden's former cook and driver has pleaded guilty at a Guantanamo Bay tribunal to conspiracy and providing support for terrorism.
In a plea deal, Sudanese-born Ibrahim al-Qosi also admitted working as Bin Laden's bodyguard in Afghanistan and helping him avoid capture by US forces.
Mr Qosi, 50, has been held at the US naval base on Cuba for eight years.
His plea represents the first conviction for the Obama administration at the controversial war crimes court.
Mr Qosi was detained in Afghanistan in 2001 and transferred to the Guantanamo Bay facility in 2002, reports say.
He faces a maximum sentence of life in prison, court officials were quoted as telling Reuters news agency.
Details of the plea deal were not immediately released.
While Mr Qosi still faces a life sentence, he may also be sentenced to time already served.