has ended his hunger strike in prison in , after demands for his immediate release.
The Egyptian British activist's mother Laila Soueif received a note from him giving her the news, the Free Alaa campaign said on Tuesday.
"I want to celebrate my birthday with you on Thursday," said in the note, dated Monday.
"I haven't celebrated for a long time, and want to celebrate with my cellmates, so bring a cake, normal provisions. I've broken my strike. I'll explain everything on Thursday."
Thursday is the scheduled day for Abdel Fattah's monthly family visit.
Visits in the jail usually go on for 20 minutes and are carried out behind a glass barrier.
Abdel Fattah, who is detained on political charges, began his hunger strike in April and had been consuming just 100 calories per day in protest of the conditions of his detention.
He commenced a full hunger strike ahead of UN climate change conference COP27, which began in Egypt on 6 November.
He also stopped drinking water on the day the event opened, but , according to a previous letter he sent his family.
Reacting to Tuesday's news, his sister Mona Seif said: "I feel cautiously relieved now knowing that at least he's not on hunger strike but my heart won't really be settled until Thursday when my mother and sister see him with their own eyes."
His sister Sanaa Seif said: "We're counting down the days until Thursday now to find out what's been going on inside prison with Alaa."
The Free Alaa campaign said the family currently has no further information about why Abdel Fattah decided to break his hunger strike.
Abdel Fattah's family has fought hard to secure his freedom and his case has resonated internationally.
The issue has played a major role in media coverage of the COP27 summit, currently being held in Egypt.
UN human rights chief last week urged Abdel Fattah's immediate release.