King Charles welcomed the president of Nigeria to Buckingham Palace on Wednesday afternoon.
President Muhammadu Buhari told journalists after the meeting that they had discussed “mostly economic” issues.
Mr Buhari said King Charles spoke “very well of Nigeria” and was “interested very much in Nigeria”.
The Nigerian leader said the meeting was initially scheduled to take place in the Rwandan capital, Kigali, during the Commonwealth Heads of Government Meeting in June but it was postponed.
President Buhari has been in London since last week for what his office called a “routine medical check-up”. He is expected back in Nigeria next week.
King Charles will later this month host the first state visit of his reign when he welcomes the South African president to Buckingham Palace.
The visit will take place from 22-24 November.
It will be the first time a South African leader has visited the UK in an official capacity in more than a decade, with the last state visit being in 2010 when Jacob Zuma visited the late Queen.