It only took 17 years, but Tom Brady's son is now just as tall as him -- and maybe even more athletic!!
The legendary NFL quarterback showed off his boy's height and his coordination in a happy birthday post Thursday ... and check it out, little Jack is all grown up!!
In a series of pics Tom threw up on his Instagram page to commemorate Jack's 17th trip around the sun, you can see he's now eye-to-eye with his 6-foot-4 father. He's got a helluva golf swing, too.