The 90-minute premiere even outperformed last summer's Idol finale by 16 percent in both adults 18-49 and total viewers, producing the highest rated night of programming in Fox history.
Idol also became the third-highest rated season or series premiere of the season in adults 18-49, behind NBC's Friends and ER, and the fourth highest among total viewers, behinds Friends, the CBS drama CSI and ER.
The Idol premiere, along with the unexpected success of Fox's limited-run reality series Joe Millionaire and the continued popularity of 24, put the network back on track to challenge for second among adults 18-49 for the season following a difficult fall start.
It also marks the first time a network has had two smash reality series on the air at the same time.
"The promotion and publicity teams here did a great job getting the word out about the show," Fox reality program chief Mike Darnell told Variety. "We thought it would do well, but we had no expectations it would do this well. It's just incredible."
Darnell added that the success of Idol and Joe Millionaire may end the debate about the public's appetite for reality shows.
"I think the genre has broadened out to a point where it's no longer one or the other," he said. "It's like saying that The Simpsons does well, so there's only so much of an audience for animation. It's all just good television."
Of course the first season of Idol also started with a bang, but cooled off mid-season. The ratings, however, heated up again as the show approached its May finale.
American Idol, which features judges Simon Cowell, Paula Abdul and Randy Jackson and host Ryan Seacrest, will begin its regular schedule--one hour on Tuesdays and half hours on Wednesdays--in two weeks.