Frederick Chopin composed his Nocturne No. 20 in C sharp minor op. posth. in 1830 for Chopin’s older sister, Ludwika, and it was first published 26 years after the composer’s death. It is sometimes referred to as the ‘Reminiscence’ Nocturne.
The melody, similar to that in many of Chopin’s Nocturnes, has a wonderful operatic quality which could be viewed as the ‘singer’ and left hand or bass clef part (the accompaniment), as the ‘accompanist’, therefore, the pianist has to engage in being both, effectively occupying both roles at once!
Here is pianist Lise de la Salle to play this music for you: