50 Cent was in da playground.

The rapper returned to his old stomping grounds in Jamaica yesterday, performing a brief surprise concert that came off without a hitch after weeks of hand-wringing by cops terrified of a riot.

As his fittiness performed his top hits such as “I Get Money,” “In Da Club” and “What Up Gangsta” to a crowd of about 2,000 in a playground near PS 40, he reminded everyone to behave themselves.

“Look at the top of the buildings – that’s the motherf- – – – – – cops. That’s the 103 [Precinct] — wave to them,” he said.