Katarzyna "Kasia" Kowalska (Polish pronunciation: [ˈkaɕa kɔˈvalska]; born 13 June 1973) is a Polish singer, songwriter, producer, and actress.

She belongs to the top rung of most frequently broadcast Polish rock artists. Kowalska is one of the best-known Polish vocalists. The estimated sale of all her albums is over one million copies, which puts her among the Polish artists with the largest number of music publishers sold in Poland.

Source: Wikipedia (https://en.wikipedia.org/wiki/Kasia_Kowalska)