WE GON' PARTY LIKE IT'S YOUR B-DAY, SON ... Even In Costume 50 cent and fam

When there's trouble, 50 Cent's kiddo knows who to call -- Mom, Dad and the whole Teen Titans crew ... especially when it's his birthday. 

50 and Daphne Joy threw their son, Sire Jackson, an epic Teen Titan-themed party for his 4th bday over the weekend at L.A. River Studios  ... and they went all out for their boy.

Check out the pics. Fitty rocked a Cyborg costume, Daphne donned a purple dress as Starfire and his grandma and aunt were Robin and Raven, respectively. 

Good to see 50 knows how to turn up in all settings ... cartoon birthdays included.