The rocker has been animated for the cult cartoon series and will appear in an episode alongside director Judd Apatow, Channing Tatum, Paul Rudd and Seth Rogen, reported Entertainment Weekly.
According to 'The Simpsons' executive producer Matt Selman, Halford performs a parody of Judas Priest hit 'Breaking the Law' to highlight cartoon stars Bart and Homer Simpson's pirated movie viewing operation.
"Even though Homer is stealing, he's doing it for the community, he's doing it out of the goodness of his heart," Selman said.
The filmmaker recalls the episode revolves around a hypnotism show that leaves Homer Simpson believing he is 10 years old.