Who wore the poodle skirt in grease?

In the musical "Grease," the character Sandy Olsson, played by Olivia Newton-John, famously wears the poodle skirt during the "Summer Nights" scene and in various other moments throughout the film. The poodle skirt is emblematic of the 1950s fashion style and represents Sandy's transformation from a sweet and innocent girl to a more confident and rebellious figure by the film's end.