Audrey Hepburn had only had one major film role—in 1953's Roman Holiday—when photographer Mark Shaw spent a day with the star. She was a 24-year-old waif (born on this day, May 4, in 1929) who had made a good impression in Hollywood and on the stage but had yet to solidify her fame. Some, like director Billy Wilder, worried that she would somehow slip through the cracks, too hard to classify, neither sex goddess nor girl next door.
The nine-page photo essay that Shaw produced for LIFE, like the outtakes seen in the gallery above, provides some hint of what made Hepburn different: rather than trailing her at parties or even in front of the camera, the photographer focused on her workaday life. She got up early for work, went to the studio, got ready to film Sabrina (referred to by the title of the play on which it's based, Sabrina Fair, in the story), practiced ballet and got ready for another day of work. The most glamorous parts of the day, the actual filming, were elided in favor of behind-the-scenes prep. But the day was a fitting subject for a photo essay, the magazine noted, "not because there is anything so remarkable about it but because whatever Audrey does, she looks pretty remarkable doing it."
As for the question of whether Hepburn would be more than a one-hit wonder, the years have provided an unassailable answer. In the decades that followed the release of Sabrina, Hepburn become one of the 20th century's most iconic stars, and it was just as photographer Shaw predicted. In a note at the beginning of the issue, he commented that she was a "monster" when it came to productivity and that the studio technicians who worked with her guessed that she would have a long and illustrious career.
"We can tell," they told Shaw, "when someone has got it."
Liz Ronk, who edited this gallery, is the Photo Editor for LIFE.com. Follow her on Twitter @lizabethronk.