It is likely that the expression "giddy up" originated as a shortened form of the phrase "get ye up," which was used to encourage a horse to stand up after lying down. Over time, the phrase came to be used more generally to encourage a horse to move forward, and it is now used to urge a horse on while riding or driving. The expression is also used to encourage or motivate someone or something to get moving or to hurry up.
Other songs that have incorporated the phrase "giddy up" in the lyrics include:
1957 "Jingle Bell Rock
" by Bobby Helms ("Giddy-up jingle horse, pick up your feet. Jingle around the clock").
1964 "My Boy Lollipop
" by Millie Small ("You make my heart go giddy up. You are as sweet as candy")
2010 "Giddy On Up
" by Laura Bell Bundy
("Ooh you won't string me along. You better be moving on. Giddy on up. Giddy on out")
2018 "High Horse
" by Kacey Musgraves ("So, why don't you giddy up, giddy up. And ride straight out of this town. You and your high horse, mmh")