Explaining how a woman acting as a droid opposite him during the audition threw him off, Tom said that he "couldn't stop laughing" and, unsurprisingly, didn't get the part.
"I remember my audition for Star Wars, I was like four or five auditions in, and I think I was auditioning for John Boyega's role," Tom told Backstage.
"I remember doing this scene with this lady, bless her, and she was just a drone. So I was doing all of this, like, 'We gotta get back to the ship!' And she was going, 'Bleep, bloop bloop, bleep bloop.'
"I just couldn't stop laughing. I found it so funny. And I felt really bad, because she was trying really hard to be a convincing android or drone or whatever they're called.
"Yeah, I obviously didn't get the part. That wasn't my best moment."
On a more successful note, Tom previously opened up about doubting his ability to play the challenging lead role in forthcoming Apple TV film Cherry.
"I, to be honest, didn't think that I could do it," he told Entertainment Weekly. "I was so excited by the idea, but then when I read the script, I really sat down and was like, 'Am I really the person for this job?'
"I probably wouldn't have accepted the job if it wasn't [directors] Joe and Anthony [Russo] making it, had I not had these two in my corner kind of guiding me through this process."
Cherry arrives on Apple TV+ on Friday, March 12.
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