Four decades into her acclaimed film career, actress Karen Allen still can't believe she ever ended up in movies to begin with.
"I was 22 and I had imagined I would just be a theater actor and live in New York," she tells PEOPLE. "Films, to me, seemed like 3,000 miles away."
That one of her first film roles happened to be in a movie that launched one of the most successful film franchises of all time — Indiana Jones — still blows her mind.
"It's extraordinary! The fact that people are still seeing the film, talking about the film, having an interest in the film, it's amazing," Allen, 69, says of still talking about Raiders of the Lost Ark all these years later. "It's amazing, and wonderful. It's just one of those films that seems like it gets passed from generation to generation, and it stayed very beloved."
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Although Allen made her big screen debut in 1978's Animal House, she is perhaps most well-known for playing Marion Ravenwood, the strong-willed and sharp-tongued love interest of Harrison Ford's Indy.
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"She walked that edge of being tough, but not being heartless," says Allen. "And their relationship too, there was love underneath all of their edginess with each other. And those are fantastically fun characters [to play], if you can find something as colorful and interesting as a woman who drinks 300-pound men under the table."
Allen says she knew very little about the role she was auditioning for when Raiders director Steven Spielberg asked to meet her.
"Steven came to New York City to meet, not just me, but some other actors he was interested in meeting for the film," she recalls. "I didn't know anything about the film. They were being very secretive about it. ... They gave me the scene in the bar, and then I was in love. I fell in love with Marion, and then I really wanted the role."
Allen auditioned with several other actors, but never Ford, who was originally thought to be unavailable for the role due to his Han Solo fame and Star Wars commitments.
"I went out [to L.A.] and I screen-tested with Tim Matheson, who had been in Animal House with me," she says. "And I screen-tested with a New York actor named John Shea, who I knew a little bit. And they asked me to do the role a few weeks later. Harrison was not even a thought in their mind, because he was Han Solo."
Allen says she was blown away by the whole experience making the film, particularly because of its scale and all of the action scenes. She's particularly proud of being able to dangle on a harness in one pivotal scene.
"I love to do stunts, I'm a very physical actor and person but the [filmmakers] draw the line when they think you might get hurt," she says. "But when I'm hanging, they put me in a harness. So I got to hang from the nose of the sculpture in the Well of Souls."
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Allen has kept busy acting since starring in the 1981 action-adventure, which nabbed a Best Picture Oscar nomination and spawned four Indiana Jones sequels (a fifth film is currently in production), and recently expanded her work in the field as a director.
"To me, [my career] is more interesting than it's ever been, because I started directing about 12 years ago," she says. "I direct a lot in the theater. And then I directed my first short film a year or two ago. I act in things when there's something interesting for me to act in. Sometimes in the theater, sometimes in films."
Allen considers being able to act and direct to be "a perfect balance."
"As the director, I get to be a storyteller and work on material that doesn't necessarily have a role for me in it, which is fine," she explains. "And I love working with actors. And I love choosing material that has some real meaning to me."
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And no matter where her work takes her, Allen will always have a special place in her heart for Marion.
"I feel like she's who I aspire to be," she says.
In celebration of the 40th anniversary of Raiders of the Lost Ark, all four movies are being released together for the first time in the Indiana Jones 4-Movie Collection.
For more on Karen Allen, pick up the latest issue of PEOPLE, now on newsstands.