 Harrison confessed that it was not easy for him to come up with the lyrics to " Crazy in Love " in that length of time . Two hours later , he had penned the verses and the hook in spite of being hung over . Harrison had also made provision for a backing track ; he played all the instruments on the track . The bridge was written by Beyoncé , who was inspired by looking at herself in the mirror ; she was not wearing matching clothes and her hair was untidy as she kept saying , " I 'm looking so crazy right now . " Harrison sang back to her and said , " That 's the hook . " It also inspired the title of the song . After that Beyoncé had filled up the middle eight , she came up with the catchphrase - " Uh @-@ oh , uh @-@ oh , you know " - alongside Harrison . 
