On his trip to the US, Ethiopia's Prime Minister Abiy Ahmed has met Berhanu Nega, who in 2009 was sentenced to death in absentia for trying to overthrow the government.
Mr Berhanu was regarded as a terrorist and his Patriotic Ginbot 7 movement was outlawed.
But Ethiopia's parliament lifted the ban on the group in May and a new amnesty law should clear the way for him to be pardoned.
The changes were part of a raft of reforms introduced since Mr Abiy became prime minister in April.
The two men held a brief meeting in Washington and discussed an agenda for a longer meeting scheduled for later on Friday, Patriotic Ginbot 7 executive committee member Tadesse Biru Kersemo told BBC Africa Live.