Farrah Fawcett (Logan's Run) Logan's Run

Farrah Fawcett played Holly 13, an assistant at the "New You" cosmetic surgery shop -- a small role in a large film that became outsized in the marketing after Fawcett became one of the most famous women in America later that year. She was credited as Farrah Fawcett-Majors, using the surname of her then-husband Lee Majors. She was twenty-nine at the time of the film's release -- one year short of her character's mandatory death age. (mentalfloss, wikipedia)

Michael York spotted her playing tennis and suggested her for the role

Before Fawcett had any significant public profile, York noticed her at a social gathering:

"I was at a friend's house and saw this extraordinary blonde beauty playing tennis and found out she was an actress. So, I went back and suggested that she might be good for Holly." -- Michael York, The Hollywood Reporter (2021)

Charlie's Angels premiered three months after Logan's Run and made Fawcett a phenomenon

Logan's Run opened on June 23, 1976. The Charlie's Angels pilot movie aired on ABC on March 21, 1976, and the series proper debuted on September 22, 1976. Producer Aaron Spelling cast Fawcett as Jill Munroe after seeing her performance in Logan's Run. Each of the three lead actresses became famous, but Fawcett dominated -- her red-bathing-suit poster sold twelve million copies, becoming the best-selling poster in history. She left the series after one season. (wikipedia, wikipedia)

The timing meant that Logan's Run posters and marketing materials were retroactively more valuable: audiences who saw the film in its summer 1976 run encountered a minor supporting player, but anyone who caught it in later months or on home video was watching a bona fide cultural icon in what amounted to a cameo.

Holly 13 appears in two beats and functions as a plot catalyst

In 40 Beats (Logan's Run), Holly appears in beats 13 and 15. She greets Logan and Jessica at New You 483, whispers to Doc that Logan is blinking and wants to run, and later arrives at the underground hideout to accuse Logan of killing Doc. Her testimony nearly gets Logan killed, but Jessica's defense -- pointing out that Francis was hunting Logan, which proves he was genuinely running -- turns the situation. Holly pauses, remembers the second Sandman, and nods. The underground votes to pass Logan and Jessica through.

Fawcett died on June 25, 2009, at the age of sixty-two. (wikipedia)