With a film crew in tow, the theorist asked the 72-year-old to swear on a Bible that he had walked on the Moon.
Uncomfortable with the situation, Aldrin repeatedly asked Sibrel to leave him alone.
However, the theorist persisted and continued to make accusations.
As tensions escalated, Sibrel called Aldrin a ‘coward’ and ‘liar,’ leading the astronaut to lose his cool.
The former astronaut was recorded swinging his fist and landing a solid punch to Sibrel’s jaw. Stunned, Sibrel stumbled backward.
The incident made headlines worldwide, with many expressing sympathy towards Aldrin for his actions given the circumstances.