Qatar's emir Sheikh Hamad bin Khalifa al-Thani Monday informed members of the royal family of his decision to hand over power to his son, Crown Prince Sheikh Tamim, Al-Jazeera television reported.
The emir of the gas-rich Gulf state, a major player on the world's diplomatic scene, will address the nation early on Tuesday to announce the transition, the report said.
Such an announcement would mark the first time an Arab leader has intentionally given up his powers.
The emir "has ended his meeting with the royal family and prominent members of Qatari society," the Qatar-based satellite broadcaster announced. "He has informed the meeting of his decision to hand power over to his crown prince."
A statement carried by the official QNA news agency said: "The royal palace announces that Qatar's emir, Sheikh Hamad bin Khalifa al-Thani, will address the Qatari people at 8:00 am (0500 GMT) on Tuesday."
A Qatari official said that the emir will "announce the transfer of his powers to his son."
The palace declared Tuesday an official holiday.
Sheikh Hamad, who used the tiny Gulf Arab state's immense gas wealth to drive its modernisation, came to power in a coup when he overthrew his own father Sheikh Khalifa in June 1995.