Julianne Moore on Most ‘Exciting’ Part of Her Career After 4 Decades (Exclusive)

After four decades in Hollywood, Julianne Moore is able to pinpoint the most thrilling part of her career.

The Oscar, Emmy and SAG-award winner, 64, tells PEOPLE in an exclusive interview that amid all the glitz, glamour and accolades that come as an A-list actress, she just loves getting to go to work at the end of the day.

“The best part of my job is the actual working, is the doing of it, because that’s what keeps me coming back,” Moore — who has partnered with Lilly to launch its new Brain Health Matters campaign — says.

“I like that creative experience. I like going in somewhere and building it with a group of people, and, in a sense, you’re all making something out of nothing, because it’s an active imagination,” continues the star.

Adds Moore: “Someone has written something down, someone is lensing it and people are pretending to be characters within it, but you are all coming together to tell this story. That’s so, so exciting for me.”

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Moore’s big break came in 1985, when she was cast in the soap opera As the World Turns, in which she played both roles of half-sisters Frannie and Sabrina Hughes. (She won a Daytime Emmy Award for Outstanding Ingenue in a Drama Series for the part.)

The actress later went on to establish herself as a leading lady in Hollywood, starring in beloved projects, including The Hunger Games: Mockingjay – Part 1 and Part 2, Magnolia, Far from Heaven, The Hours, The Big Lebowski and May December, to name a few.

Moore has earned multiple awards, and she has also scored wins at various industry events over the years, including the Cannes Film Festival and the Venice Film Festival.

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Moore has been nominated five times at the Academy Awards, and she won in the Best Actress category for her film Still Alice in 2015. Recalling the first time she was nominated for Boogie Nights, the mother of two tells PEOPLE, “I couldn’t believe it. That was a moment that was really strange for me, because I’d been out of it, because I just had a baby, and when the nomination came in, I was like, ‘What?’ ”

“I’d been spending all this time taking care of this teeny baby, and you’re not terribly conscious afterwards, you’re still floating around in a haze of early motherhood, and then suddenly there was this Oscar nomination,” adds Moore. “All of that seemed to be just kind of crazy, and I think having them happen together like that, that was something I couldn’t quite wrap my head around.”