She re-scaled many ballets and expanded them to a new level of technique. In 1965, she was promoted to principal dancer. Her first role in her new title was "Agon" with Arthur Mitchell at the Paris Opera. George Balanchine quickly fell in love with his "alabaster princess" and created many roles for her. Farrell described learning choreography from Balanchine as a collaborative process, saying, "When Mr. B was working on a ballet, something would just spill out of his body; he could rarely duplicate it, so I tried to see precisely what he wanted the first time."