Rex Gildo (July 2, 1939 - October 26, 1999) was a German singer of schlager ballads who reached the height of his popularity in the 1960s and 1970s, selling over 25 million records and starring in film and television roles.

Gildo was born Ludwig Alexander Hirtreiter in Straubing, Bavaria and was a member of the Regensburger Domspatzen choir before going to acting school. His first performance was with the Munich Kammerspiele theatre group in 1956