A harp creates completely different overtones than a grand piano, which makes a big difference between singing with the accompaniment of a harp, and a grand piano. The singer has to adjust the ears to a completely different sound that partly supports the song well, but also makes it difficult for the singer to intonate; the singer is more vulnerable than with a piano accompaniment. The harp's design makes it hard for the harpist to quickly make key changes and modulations, that for a pianist is natural, or even simple. Sometimes the key has to be adapted to the harp's capability. A good and direct communication between singer and accompanist is always essential, regardless of accompaniment. Even a flexible and sensitive harpist can experience more difficulties to shift tempo than a pianist, forcing the singer to phrase different than singing to the piano or guitar. However, such difficulties must be tackled and afterwards the cooperation can be rewarded with an emergence of a magical atmosphere. Since the harpist Stina Hellberg Agback is also a skillful improviser, another dimension is added, here in the songs by George Gershwin.