Rosa Lee still lives and performs in Los Angeles. According to her not only did Hendrix play on "My Diary" and "Utee", in addition they also had a relationship during Hendrix's stay in Los Angeles.
Read more about Rosa Lee Brooks on her myspace-website.
Hendrix himself never mentioned the Rosa Lee Brooks single, but both Arthur Lee of Love (who composed "My Diary") and Rosa Lee Brooks have stated that he played guitar on the session. Arthur Lee says that he met Jimi Hendrix when Billy Revis recommended him as someone who could play in the style of Curtis Mayfield.