Detroit Lions RB -- Happy Birthday Bro ... YOU GET A CAR! (VIDEO)

Detroit Lions running back Ameer Abdullah might be the best lil bro ever -- 'cause he just surprised his older sibling with one helluva birthday present ... A NEW CAR!

The 22-year-old -- who's still in his rookie contract (4 years, $4 mil) -- hooked up his brother, Kareem, with a black Chevy Camaro ... and recorded the gift-giving moment for all to see!

"I use to dream of times when I could do things like this for the family and there's no one more deserving than this guy right here," Abdullah said.

"This for all the times you believed in me when I wanted to quit on myself! We on now! Happy early birthday bro you deserve it!"

It's an awesome gesture, just one potential problem ... Ameer has 7 OTHER SIBLINGS!!