She said that Uhuru, who was ten years then, used to sneak her a soda when she visited State House to entertain former President Jomo Kenyatta.
In the video, Muthoni approached Uhuru at the podium and whispered something which left the president tickled.
She told K24 in an interview that she frequently visited State House way before Uhuru was born and became friends with the latter in later years.
"I asked him if he remembers how he used to steal soda for me. After that, he told the people in the podium about it," she said in the Friday interview.
Muthoni added that getting to the podium where Uhuru and other leaders were seated wasn't easy and had to be aided by former Kamukunji MP Maina Kamanda.
She is set to visit State House next week with other artistes who received an invite to chart ways on improving their welfare.
Uhuru, Deputy President William Ruto, and former Prime Minister Raila Odinga led mourners to pay their last respects to Kamaru in Murang'a.
The leaders described the late Kamaru as a legend who used his music to pass the message of peace and love.