The A-list star, 51, made an unannounced appearance at The Joanne Baron & D.W. Brown Studio graduation this weekend, and delivered an inspiring speech to its shocked graduates, according to the New York Post and fans on Twitter.
The speech touched on how the mega-star got the acting bug, made inroads in the business, and offered advice on staying humble after that first big break.
He told the group that as a kid, "I liked to make people laugh. I really enjoyed making my mother laugh and my sister laugh."
His unofficial training consisted of seeing lots of movies in the theaters, and he said he worked odd jobs cutting lawns, delivering newspaper and selling Christmas cards starting at age 8 to raise money for the tickets.
After moving to New York, he recalled landing his first film job, Taps, with Timothy Hutton, George C. Scott and fellow newbie Sean Penn, which "was a formative moment for me."
"It was an incredible experience," he recalled. "I remember at night I couldn't sleep because I thought: 'This is my dream. I love it so much being part of this group and seeing what this process is like.'"
He said those first four weeks of rehearsals were eye-opening, particularly since he never had formal training before.
"I thought, well, if I never have a chance to make another movie I'm just going to learn as much as I can," he recalled. "So I went to every single department and spent time there ... I drove [cinematographer Owen] Roizman crazy asking about lenses and film ... I didn't even know what a mark was!"
The audience loved it.
"That he took time out of his incredibly busy schedule to speak to a graduation class of 60 students was overwhelming," student Greice Santo told the Post.
"Even with all his fame he seemed authentic," another source told the paper, and added that Cruise's cousin, fellow actor William Mapother, is a graduate of the school.