 " My Boo " is a hip hop @-@ <unk> R & B song with a mid @-@ tempo melody . It is composed in the key of D minor , in common time . The lyrics are constructed in verse @-@ chorus @-@ chorus form . Usher starts the intro , and Keys followed her rap @-@ intro , with background vocals from Usher . He proceeds to the first verse and chorus , leading to Keys singing another chorus , altering some of the lyrics of the original chorus to create a dialogue . Keys sings the second verse and Usher for the chorus , with background vocals from Keys . Keys repeats her version for the chorus . The song breaks with Usher and Keys singing " My oh , My oh , My oh , My oh , My Boo " , one after the other . Usher repeats the chorus again , and they sing the intro of Keys . 
