Singer Piyush Mehroliyaa, who is known for the song 'Aawara Shaam Hai', has lent his vocals to the song 'Sun Sajni' from the upcoming Kartik Aaryan and Kiara Advani-starrer film 'Satyaprem Ki Katha'. The singer has revealed that he didn't know that his voice will be used for the on-screen portrayal by Kartik.