Mohamed Fahmy, one of two al-Jazeera journalists still held in Egypt, has renounced his Egyptian citizenship to secure his release, his family said.
Fahmy's brother said the journalist, who is also Canadian, was told to give up either his nationality or his freedom.
Canada says his release is imminent. The status of his Egyptian colleague Baher Mohamed remains unclear.
Peter Greste, who was freed Sunday, said he felt "incredible angst" at leaving his colleagues in a Cairo jail.
The Australian journalist was freed from prison and deported after 400 days behind bars.
The three Al Jazeera journalists were arrested in 2013 after being accused of collaborating with the banned Muslim Brotherhood following former President Mohammed Morsi's ouster by the military.
All three denied the charges against them and said their trial was a sham.
Fahmy's brother, Adel, told reporters that the Egyptian authorities gave the journalist the choice between "dropping the nationality or your freedom".
"It was a very difficult decision. Mohamed is very proud and comes from a patriotic family of high-ranking military and policemen that have defended this country and fought its wars," Adel Fahmy said.
Many of his family members were offended by Fahmy's decision to relinquish his citizenship, he added, but said his fiance and his mother pushed him into doing so.
Canadian Foreign Minister John Baird had said Monday that Fahmy's release was "imminent" but gave no details of a resolution.
In June last year, Fahmy and Greste were sentenced to seven years in prison and Mohamed to 10. Their sentences sparked an international outcry.
The three men's convictions were overturned Jan 1 but they remained in custody pending a retrial.
