Retired boxing champ Mike Tyson has issued a word of warning to his pal 50 Cent as he prepares to become a sports promoter, insisting dealing with fighters in the ring is a tough job.

The "In Da Club" star recently launched TMT (The Money Team) Promotions to help organize future bouts for his good friend Floyd Mayweather, Jr. and he has been busy signing other boxers to the new firm.

But Tyson claims 50 Cent will have a lot to learn about how to do business in the sports world and he hopes the rapper will find success in his new venture.

He says, "I wish 50 Cent the best of luck in the world with the endeavour that he's doing, but this is something that 50 Cent has to know when you're dealing with something like boxing and you're dealing with human beings. We calling it peddling the flesh. Even though you're paying them, you're still dealing (with) flesh..."

"50 is a rap star, 50 is an entertainer, 50 is an entrepreneur. He doesn't really know the ins and outs of boxing."