 Before recording the song "Youre Just in Love", Donald  OConnor (qv) felt that it would produce better effect if he sing  the song with Ethel Merman (qv) in the studio with the orchestra.  Alfred Newman agreed and let them sing together. It turns out that  Mermans singing voice was too deafening for OConnor. In the end,  they had to record the song with OConnor in the isolation booth.  When filming the musical number, OConnor had to wear ear plugs.