So far I have found this article and interview with Mandela.
What do Haile Selassie and Mandela have in common? Among other things, both are Africa’s most prominent politicians who have come to be considered as inspiring and iconic figures of our age. Though one was a symbol of regal and feudal power and the other a revolutionary with Marxist inclination, both have come to demonstrate great political ability and astuteness during their period in office. Both suffered colonial oppression, and both of them mobilized their respective peoples against oppressors that violated their freedoms. Both are cool, self-contained men, who managed to stay calm and graceful under pressure.
In 1962, the burly, black-haired Mandela came to Ethiopia seeking military and political training to fight apartheid. At a young age and without much experience as a freedom fighter, Mandela was thrilled to see and meet the black independent sovereign who already gained prominence in the international scene. The following excerpt from Nelson Mandela’s new book, Conversations With Myself, renders a portrait of Haile Selassie based on a meeting with the Ethiopian Emperor in military parade in Addis Ababa. From a recorded conversation with Time magazine editor, Stengel, we could see that Mandela was clearly impressed by the Emperor’s statesmanship. He spoke few words given their distant acquaintance but they will carry immense weight simply because of who he is. Describing the Emperor as “an impressive fellow man, man, very impressive”, Mandela adds: “It was my first time to watch…a head of state going through the formalities.” Here is the whole text.
Conversations with Richard Stengel about meeting Emperor Haile Selassie of Ethiopia
STENGEL: So tell me about the Emperor, Haile Selassie. You met him.
MANDELA: That was an impressive fellow, man, very impressive. It was my first time to watch…a head of state going through the formalities… the motions of formality. This chap came wearing a uniform and he then came and bowed. But it was a bow which was not a bow –he stood erect, you see, but just brought down his head…then…took his seat and addressed us, but he spoke in (Amharic)…Then, at the end of the conference he saw every, each delegation…and Comrade Oliver Tambo asked me to speak for our delegation, to speak to him. And I explained to him very briefly what was happening in South Africa…He was seated on his chair, listening like a log…not nodding, just immovable, you know, like a statue…The next time I saw him was when we attended a military parade, and that was very impressive (whistles), absolutely impressive. And he was then giving awards…to the soldiers; everyone who had graduated got a certificate… A very fine ceremony-a very dignified chap- and he also gave medals. There (were) American military advisors… (and) groups of military advisers from various countries …And so he gave medals to these chaps too. But to see whites going to a black monarch emperor and bowing was also very interesting.