Tinubu has been out of Nigeria since early July to attend to a nagging knee injury sustained decades ago as a school boy.
He had surgery in Chicago, United States in August and has been recuperating in the UK since then.
On Saturday, Tinubu and Buhari jointly attended the inauguration of the Democratic Progessive Movement. The event held at the Methodist Central Building in Manchester City.
Buhari also gave the inaugural lecture titled: “Discipline and Accountability under democratic Leadership’.