The two-hour debut of Season 5 on last Tuesday, featuring celebrity judge Simon Cowell viciously critiquing aspiring pop stars auditioning in Chicago, averaged 35.5 million viewers, according to preliminary figures.

Early episodes of the show focus on tryouts around US to select semifinalists who come to Hollywood, where they compete in weekly elimination rounds for a shot at fame and a recording contract.

Cowell was at his brutal best on Tuesday, comparing one woman's voice to the sound of screeching cats and urging a male contestant to shave off his beard, put on a dress and become a female impersonator.

Except for ABC's telecast of the Rose Bowl college football championship earlier this month, which drew 35.6 million viewers, the return of Idol ranked as the most watched US television programme so far during the 2005-2006 season, Nielsen said.

The final episode of Season 2, in which Ruben Studdard was crowned the winner over Clay Aiken, holds the record as the most watched American Idol broadcast -- at 38.1 million viewers overall.

Aside from becoming Fox's most important property, it also has become an incubator for fresh talent in the US recording industry.

All eight winners and runners-up from the first four editions of the show have been signed to either J Records, RCA Records or Arista Records under Sony BMG's RCA Music Group.