A multimillionaire CEO who starred on TV’s Undercover Boss is being accused of spying on a competitor.

Mitchell Modell, the flamboyant Chief Executive of the Modell’s Sporting Goods chain, posed as a Senior Vice President of Dick's, a rival retail giant, according to a lawsuit.

The lawsuit claims Modell dropped in at a Dick's Sporting Goods store in New Jersey last month, persuaded staff to show him the back rooms and peppered them with questions about some of the company's most closely guarded secrets.

Lawyer John Q. Kelly told INSIDE EDITION, "Through deception, through trickery, they can get access to your back offices and your proprietary information, and that is just flat out wrong."

Modell appeared on the hit reality show Undercover Boss in 2012. He shaved his head and wore a wild mustache to hide his identity. But even in disguise, he was discovered by an eagle-eyed employee.
 
Modell's appearance on Undercover Boss was emotionally charged. The multimillionaire wept when he discovered one of his minimum wage employees, named Angel, was living in a homeless shelter. She collapsed when he gave her $250,000.

His alleged escapade at Dick's could cost much more than that. His rival wants millions of dollars in damages.     

Dick's said in a statement: "Dick's Sporting Goods takes seriously the protection of its confidential and proprietary information."