Uyimbube is a Zulu phrase meaning you are a lion. It was a lyric in a song written by an African singer of Zulu origin named Solomon Linda. The song was recorded in the 1930s. It was called Mbube.
Eventually, the song made its way to the international stage and was recorded by The Weavers as a song called Wimowah, which was a mis-hearing of the word Uyimbube from the original song.
We all know the song as The Lion Sleeps Tonight- here is the familiar version by The Tokens: