One of the year's bestselling rap hits, Jay-Z's "Big Pimpin' " embraces all the genre's favorite themes: cars, babes and great wads of cash. But while the lyrics are home-grown, the now-famous riff that fuels the song is straight out of Cairo.

As in Egypt. The twitter of flute notes throughout "Big Pimpin' " is a nearly note-for-note knockoff from "Khusara," a 40-year-old tune sung by Abdel-Halim Hafez, a vocalist who achieved Elvis Presley-like stature in Egypt.

You'd never know that detail from Jay-Z's album "Vol. 3: The Life and Times of Sean Carter." Nearly every other song on "Vol. 3" credits someone for a hook or sample--except "Big Pimpin'," which is silent about the song's musical origins. That infuriates "Khusara's" original producer and current copyright owner, Magdi Amroussi, who is very much alive and, apparently, a little peeved.

Lifting the riff "is a crime that they should be punished for," Amroussi told Egyptian reporter Tarek Atia of Al-Ahram Weekly.

Punishment is unlikely, nor is Jay-Z going to fork over royalties any time soon, since the song probably doesn't infringe directly enough to sustain a copyright suit. (The riff has been tinkered with ever so slightly, and re-recorded by a new flute player.)

That's sure to put Amroussi in an even worse mood because "Big Pimpin' " has undoubtedly generated big money. The song has clung to Billboard's rap charts for more than 20 weeks and helped "Vol. 3" reach platinum status. It became such a radio staple that actor Jim Carrey rapped a few bars recently on "The Tonight Show," wondering aloud if anyone knew what Jay-Z means when he spells "B-L-A-D" in the chorus. (He's referring to Blades, a brand of chrome car-wheel rim, if you're interested.)

So how did a 40-year-old Egyptian melody end up on a rap song? The idea, it turns out, came from the song's producer, a 26-year-old who goes by the name Timbaland. And Timbaland heard it, as best he can recall, at a carnival.

"I remember hearing it and then I just hummed it to some friends. Then we hired an old guy to play it on an Arabian flute," he said in a phone interview. "If you're an innovative producer you hear stuff, at the circus or on TV, and you use it."

Timbaland didn't know that the song was called "Khusara," nor did he seem to care.

"It's just an ill sound," he said. "It makes me think about summertime, a bunch of girls and king cobra coming out of genie bottle."