Listen to What a Day That Will Be (Instrumental Version) online. What a Day That Will Be (Instrumental Version) is an English language song and is sung by The O'Neill Brothers Group, Instrumental Christian Songs and Christian Piano Music. What a Day That Will Be (Instrumental Version), from the album Songs of Faith - Ukulele Instrumentals, was released in the year 2018. The duration of the song is 2:52. Download English songs online from JioSaavn.