Los Angeles (Agencies): 'American Idol' bosses have issued a public apology on behalf of new judge, 'Aerosmith' rocker Steven Tyler for using a slur word.

In contrast to the normal montage of excited contestants, last night's 'American Idol' began with a somber apology.

The screen went black and a message read, "American Idol would like to apologize for last week's outrageous behaviour by Steven Tyler. Mr Tyler has been warned and assures us it will never happen again."

The behaviour in question was screened on previous week's show when a contestant named Jake Muck walked onto the audition stage in Austin, Texas.

Tyler told him. "You know what Muck rhymes with, don't you?" The contestant replied, "Duck". To which Tyler said simply, "Read my lips".

But the apology left many fans baffled, questioning on social media sites whether there was any need to apologise, as the producers had chosen to leave the footage in the edited show.

Bosses at Fox, who produce the show, have not said whether any viewers complained about the joke.