Not being familiar with Ridley's original Internet work, I can't state whether the rip-off started back then, but the fact that the film's other screenwriter, Michael McCullers, also co-penned the second and third "Austin Powers" films gives one the impression that he may have had a little more than something to do with the rather obvious similarities.
Or at least, a little different from the Austin Powers films.
You can tell that writer John Ridley enlisted the help of Austin Powers scribe Michael McCullers for the screenplay of Undercover Brother.
Just as Austin Powers: International Man of Mystery spoofed '60s British spy movies, Undercover Brother riffs wildly on the heroic ghetto action films of the '70s, embodied in Jim Kelly, Fred Williamson, Pam Grier and Richard Roundtree.
"Austin Powers" meets "Shaft" might have been the pitch, but that would have been a good movie.
Lee wants “Brother” to be his “Austin Powers,” using cheap and unfunny retro jokes and pop culture satire to seed his own desire for a franchise to call his own.