Diddy gives his 17-year-old son Justin a $390,000 limo after he makes the honor roll.

Diddy pays big for good grades -- to the tune of a $390,000 Mercedes Maybach limousine.

"Justin has turned himself around and is now an honors student, which he wasn't before, so I wanted to treat him," Diddy said. "It's a collector's car so maybe he will use it for special occasions like on a first date, but like all my kids, he prefers the simpler things [more] than the expensive things. Simple tastes."

This isn’t the first big gift Diddy has given his son. When Justin turned 16, he got another Mercedes Maybach worth over $300,000.

Diddy is also a father to 12-year-old Christian, twin girls D’Lila Star and Jessie James, 4, daughter Chance, 4, and stepson Quincy, 19.

The rap mogul defended his big gifts during an interview with Martin Bashir.

"The whole thing about giving a Maybach to my son, that's really like a racist question. You don't ask white people what they buy their kids," Diddy said. "And they buy them Porsches and convertible Bentleys, and it ain't no question. It's really a racist question and put things back in perspective with money and the way that people still look at you. And I'm not saying that consciously [Bashir's] a racist. But he probably don't even realize that he would not ask Steve Jobs that. He would be like Steve Jobs has that money, and that's the gift his kid is supposed to get."