Frederik (real name Ilkka Juhani Sysimetsä, born February 2, 1945) is a Finnish singer. He is known by his nickname Reetu.[1] During his lengthy career, he has been awarded five gold and three diamond records. One of his contemporary nicknames is Junttidiscon kuningas (King of hillbillydisco).
Some of his best-known songs are Jos jotain yrittää (Harva meistä on rautaa), Linda Linda, Tsingis Khan, Sheikki Ali Hassan, Titanic, Stenka Rasin, Kasakkapartio, Volga, Kung-Fu Taistelee and many more.