South African-born billionaire businessman Elon Musk worked illegally in the United States during a brief period in the 1990s while building a startup company, the Washington Post reported on Saturday.

Elon Musk has denied reports that he worked illegally while on a student visa in the United States after a bombshell story in The Washington Post claimed the South African-born tech mogul once admitted he “had no legal right to stay in the country.