Why they sound alike
The choruses to both Let It Go (2014's Best Original Song Oscar-winner from the animated pic Frozen) and Sunflower (released 2009) by Korean actor Park Sang Min, share melodies and chord progressions (though in different keys, LIG: Ab major vs Sunflower: C major). Both utilize a , I-V-vi-IV (or 1-5-minor6-4) chord progression, found in myriad songs, including Let It Be, Don't Stop Believin', and With Or Without You. However, the melodies are very similar. Let It Go (1:00) VS Sunflower (2:55).
