The world's best known "wardrobe malfunction", which bared Janet Jackson's right breast in front of 90 million television viewers, will be back in court today.

The 3rd US Circuit Court of Appeals in Philadelphia will hear arguments about Jackson's appearance during the half-time show of the 2004 Superbowl, when American football fans watched Justin Timberlake rip off part of the singer's bustier, briefly exposing her breast.

The Federal Communications Commission (FCC) fined CBS Corp $550,000 (£275,000) over the incident (see video), which provoked half a million viewer complaints.

CBS challenged the fine, claiming “fleeting, isolated or unintended" images should not automatically be considered indecent which the FCC disputes.

The case is being argued at a time when the FCC's enforcement regime regarding broadcast indecency is in a state of flux.

In June, the 2nd US Circuit Court of Appeals rejected by a 2-1 vote the agency’s polices on indecent speech in a case involving the one-off use of the f-word by celebrities at the Billboard Music Awards.

The court rejected the FCC’s policy on procedural grounds but was “sceptical that the commission can provide a reasoned explanation for its fleeting expletive regime that would pass constitutional muster”. Government lawyers may appeal against that decision in the Supreme Court.

Meanwhile Congress is considering a Bill sponsored by two Democratic Senators that would require the FCC “to maintain a policy that a single word or image may be considered indecent” although it would not be retroactive. The American Civil Liberties Union said the bill “could have serious and damaging effects on the First Amendment,” which protects free speech.

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