Rush, the band, has formally forbidden Republican shock jock Rush Limbaugh from using their music on his radio program.

The Canadian supergroup was contacted by The Huffington Post's Bob Cesca this week and asked if they gave Limbaugh permission to use their music. They responded by sending Limbaugh a cease and desist letter through their attorney.

Limbaugh has long made use of Rush's music, and even played the track "The Spirit of Radio" in the background as he insulted Georgetown law student Sandra Fluke, calling her a "slut" and a "prostitute" because she vocalized support for universal contraception coverage through private health insurance.

"The use of Rush's music in this way is an infringement of Rush's copyrights and trademarks," the band's letter (PDF) reads. "The public performance of Rush's music is not licensed for political purposes and any such use is in breach of public performance licenses and constitutes copyright infringement. There are civil and criminal remedies for copyright infringement, including statutory damages and fines."

Rush is the second music group to demand that Limbaugh stop using their material without permission. They followed artist Peter Gabriel, whose music was also played during the inflammatory segment.

So far, a total of 38 advertisers have dropped their placements on the Limbaugh show over his offensive, sexist comments. They include JC Penny, Capitol One, Netflix, AOL, Allstate Insurance, Quicken Loans and, among others.

Fluke said she's considering a slander lawsuit against Limbaugh over his remarks.