I Gotta Know by Elvis Presley is in G at 120 beats per minute and runs 2:16 across 32 bars. It uses 7 chords — G, G7, C, D7, N.C., Em, A7. The chord diagram changes as the song plays and the words light up as they are sung, so you can strum and sing along without reading ahead.
Want the melody line note by note? I Gotta Know guitar melody tab.