Mr. Kofi Annan's immediate successor as Secretary-General to the United Nations, Mr. Ban Ki-moon, has said he had a mental shock when his immediate predecessor's death was announced to him.

Mr. Annan died in Bern, Switzerland, on Saturday, 18 August 2018. He was 80.

His family and the Kofi Annan Foundation said in a statement that the Nobel Peace Laureate, "passed away peacefully", after a "short illness".

The late U.N. Chief was buried at a military cemetery in his home country Accra, Ghana, after a state funeral was held in his honour.

Mr. Annan won the Nobel Peace Prize for his far-reaching humanitarian work in 2001.

The Ghanaian diplomat was also the first black African to serve as U.N. Chief. He served two terms, from 1 January 1997 to 31 December 2006.

Speaking in an exclusive interview with Class91.3FM's Executive Breakfast Show host Moro Awudu in New York on Friday, 21 September 2018 ahead of a scheduled memorial service to be held in honour of the late top diplomat at the UN headquarters, Mr. Ban Ki-moon said: "I had been guided by his wisdom and experience as Secretary-General of the UN, but first I had known him since 2001; way back when I was serving as Chief of Staff to the president of the General Assembly... when Korea was serving as president of the General Assembly".

"We had a very close relationship", Mr. Ban Ki-moon said, adding: "He came to Korea when I was Foreign Minister, in his capacity as Secretary-General. All in all, we had been meeting very often … he is a man of vision and he has been widely respected for his courageous vision and commitment to human rights and justice".

The eight U.N. Secretary-General said Mr. Annan's death dealt him a big shock because "we celebrated his 80th birthday in May in London; until that time, he looked pretty healthy and fine".

"I was so shocked when I heard that he had passed away suddenly", Mr. Ban Ki-moon said.

"I received the first news from the spokesman of the United Nations, and it was a total shock, in fact it affected me – sort of a mental shock; how come he left us so suddenly?"

He eulogised Mr. Annan as a great leader, saying: "I know that he is a monumental leader with a great vision, he's a man of humanity, he's a man of commitment, that's why all the world's people are grieving over his death and I wish all the people of Ghana [my condolences].

"He had been a very proud son of Ghana and the world, of course, so, Ghanaians should have all the reasons to be very proud of a dear son and may he rest in peace and eternity".

"I'm invited as his immediate successor" to the memorial service, Mr. Ban Ki-moon said, "And I'm honoured to say a few words. A few weeks ago, I wrote an obituary to the Time Magazine, which you might have seen; that's what I really wanted to say to the people of the world: Let us carry on the legacy of Kofi Annan for humanity, peace and development and I'm sure that the flame of his legacy will continue to burn in this world brighter and brighter".