Tom Cruise had spent the 1980s looking like Hollywood had personally invented the concept of effortless cool, and then Rain Man arrived to ruin the party. Charlie Babbitt was no Top Gun dreamboat; he was a grasping car dealer chasing a $3 million inheritance, treating his autistic savant brother Raymond less like family and more like an inconvenient ticket to a fortune. Cruise made the unpleasantness compelling, then quietly let Charlie’s arrogance and greed collapse into something considerably more human.

Thirty-eight years later, Rain Man's director looked back and admitted that Cruise had a quality in his performance that surprised him enormously.

Barry Levinson recently revisited the making of Rain Man while speaking to PEOPLE, and one surprise still sticks with him: Tom Cruise’s improvisational instincts. Levinson watched Cruise and Dustin Hoffman build Charlie and Raymond’s unusual relationship, but Cruise’s ability to improvise genuinely caught him off guard. It was an unexpected skill from an actor better known for his polished screen presence.

“And the two of them were wonderful together, Dustin and Tom, because we had to do a lot of improvisational things as we went along, and Tom was not known for that, but was exceptionally good,” he said.

Levinson remembered that Rain Man gave Cruise and Hoffman plenty of room to discover Charlie and Raymond on the road, rather than simply marching through a predetermined script. Their cross-country journey gradually transformed two estranged brothers into something resembling a family. Levinson made clear that the performances were central to making that emotional evolution feel so natural.

Rain Man then turned that intimate character story that Levinson was talking to PEOPLE about into a spectacular commercial success. Made for $25 million, the film grossed more than $350 million worldwide and became the highest-grossing movie of 1988. Its success continued at the Academy Awards, where it won four Oscars, including Best Picture, Best Director, Best Actor for Dustin Hoffman, and Best Original Screenplay.

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If Digger left critics divided, Tom Cruise’s improvisational track record tells a rather different story, packed with moments he helped create on the fly.

Tom Cruise’s improvisational talent becomes much clearer when you look at what he actually changed on set. For Risky Business, the script merely called for Joel to dance in his underwear, yet Cruise created the now-famous routine himself, sliding in socks, using a candlestick as a guitar, jumping on furniture, and playing to the music. The scene became iconic precisely because Cruise supplied the personality the page barely contained.

Top Gun offers an even more revealing example because Cruise turned a mistake into one of the film’s defining romantic moments. After forgetting his scripted line during a scene with Kelly McGillis, Cruise did not stop the action or wait to recover the dialogue; he stayed in character and kissed McGillis instead. The spontaneous choice worked so well that the filmmakers kept it, demonstrating Cruise’s ability to react instinctively without sacrificing the scene’s emotional rhythm.

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Who would have guessed that beneath all that Tom Cruise precision lies a rather impressive improvisational streak? Let us know in the comments!