Janet Jackson was exposed during a routine with Justin Timberlake

The Federal Communications Commission (FCC) fined CBS $550,000 (�307,000) for the infamous "wardrobe malfunction".

The FCC said given the public outcry that followed, "it was CBS and not the commission that was out of touch with the standards of the American people".

More than 500,000 complaints were received after the broadcast.

CBS apologised after the incident.

In its appeal, it argued that the FCC wrongly applied the decency standard and the show had not intended to shock.

In March, the FCC rejected the television network's first appeal but allowed it to ask the regulator to reconsider the ruling.

'Accident'

"The commission affirms its finding that CBS' violation was wilful and declines to reduce the forfeiture imposed upon CBS," the FCC said in a statement.

"We find that CBS has failed to present any argument warranting reconsideration of our forfeiture order."

The fine was the largest ever levied against a US television broadcaster.

Jackson exposed her right breast during a dance routine with Justin Timberlake during the Super Bowl's halftime show two years ago.