Cannon was a millionaire music star by the age of 18, but frittered the cash away on luxury cars and jewellery.
He worked with his friend Smith on a TV show in 2001 and Cannon learned a valuable lesson about money from his pal.
Cannon tells the Wall Street Journal, "I became a millionaire and went broke all before the age of 19. I spent it right away and did a lot of frivolous, unintelligent things with the money.
"I bought jewellery and Range Rovers... instead of buying property I was leasing the most expensive property, and then you turn around and you owe the government 44 per cent of what you made and you don't understand that, even when people you tell that.
"One of those who was a mentor to me at that young age and opened a lot of doors was Will Smith. I remember when I was going to buy the Range Rover he said, 'Man, don't go buy that, you don't need that'.
"He was someone who made $1 million and lost it at a young age, so you got to pay attention to the people who came before you."