<Table> <Tr> <Td> </Td> <Td> "Believe It or Not" (1981) </Td> <Td> "When She Dances" (1981) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> "Believe It or Not" (1981) </Td> <Td> "When She Dances" (1981) </Td> </Tr> <P> "Theme from The Greatest American Hero (Believe It or Not)" is a song composed by Mike Post with lyrics by Stephen Geyer, and sung by American singer Joey Scarbury . It serves as the theme song for the 1980s television series The Greatest American Hero . The track was later included on Scarbury's 1981 debut album America's Greatest Hero . </P> <P> The theme song became a popular hit during the run of The Greatest American Hero . "Believe It or Not" debuted in the Top 40 of the Billboard Hot 100 on June 13, 1981, eventually peaking at number 2 during the weeks ending August 15--22, 1981, kept off the top spot by "Endless Love" by Diana Ross and Lionel Richie, and spending a total of 18 weeks in the Top 40 . On the Adult Contemporary Chart, "Believe It or Not" went to number 3 . It also peaked at the number 1 position on the Record World chart . </P>

Who sang the theme to greatest american hero