He and his aides “strongly” denied the charge, which carries a sentence of at least 15 years. Those found guilty can also be sentenced to death.
But all charges have now been dropped, apparently after a visit by Commonwealth Secretary General Patricia Scotland, who was in Zambia last week and met Mr Lungu and Mr Hichilema.
She later hinted Mr Hichilema could be released in the public interest.
A source had earlier told the BBC he was “definitely being released today… unless there’s a last minute development”.