President Muhammadu Buhari resumed work, on Monday, at about 11:20am.
Acording to The Sun newspaper, the president did not go to his office, but chose to operate from his official residence.
A Presidency official told State House told reporters that this was because the president’s office was being renovated.
The official, who pleaded anonymity, said the president would move to his office as soon as the renovation was completed.
Speaking to State House correspondents later, presidential spokesman, Mr Femi Adesina, confirmed that the president had resumed work and transmitted a letter to the National Assembly.
Later in a statement, Adesina said Buhari, in line with constitutional provision, had written the National Assembly, notifying the legislature of his return to office, after returning from medical vacation in London.
President Buhari had left for London on May 7, 2017, and handed the reins of government to the Vice President, Prof Yemi Osinbajo, who functioned as the Acting President.