This “Pretty Boy” is off to prison.

Gavin “Pretty Boy” Marchand, brother of rapper Foxy Brown, turned himself in at a Manhattan courthouse yesterday, and will begin a prison stint of at least 2 1/2 years for a pair of credit-card ID thefts.

Marchand, 36, was arrested in the summer of 2010 for using bogus cards linked to real accounts to buy $8,000 in designer duds at the Hermes store on Madison Avenue and pay a five-figure bar tab at Nikki Beach Midtown nightclub.

The long sentence — a parole board could keep him in for up to five years — was the result of his prior felony ID-theft record and the weight of evidence against him.