Cliff Robertson's 5 Most Iconic Roles

The Oscar winner, whose credits include "Charly" and "Spider-Man," died Saturday, one day after his birthday.

Oscar-winning actor Cliff Robertson died of natural causes Saturday, one day after his 88th birthday, at Stony Brook University Medical Center on Long Island, Evelyn Christel, his personal secretary of 53 years, told the Associated Press. 

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Here are his five most iconic roles:

Charly: The 1968 movie stars Robertson as the title character, a mentally impaired bakery worker who becomes the subject of an experiment intended to increase human intelligence. Robertson earned an an Oscar for best actor for his role in the movie, which was adapted from the novel Flowers for Algernon by Daniel Keyes. Charly, directed by Ralph Nelson, co-starred Claire Bloom, Lilia Skala, Leon Janney and Dick Van Patten.

PT-109: Robertson took on the role of a young John F. Kennedy in the movie, which told the story of Kennedy's herioc World War II exploits as a P.T. boat skipper. In fact, the president himself suggested Robertson for the role, which turned out to be one of his most popular performances.

STORY: Oscar-Winning Actor Cliff Robertson Dies at 88

J.W. Coop: In 1972, Robertson proved he could do more than act with this gritty yarn about a rodeo cowboy, on which he served as producer, director, writer and star. The movie, featuring footage from actual rodeo events, was made with the cooperation of the Rodeo Cowboys Association (later the Professional Rodeo Cowboys Association).

AT&T: Robertson served as AT&T's national spokesman for 10 years, a role that earned him an Advertising Age award for best commercial.

Spider-Man: Robertson is perhaps best known to younger audiences as Uncle Ben Parker, the uncle to Tobey Maguire's Peter Parker in Sam Raimi's Spider-Man trilogy. "Since Spider-Man 1 and 2, I seem to have a whole new generation of fans," the actor wrote on his website. "That in itself is a fine residual."