UPDATED: Fox has broken its tie with CBS to become the top-rated network for the season.

As of Tuesday night, when Fox aired two hours of “American Idol,” the network has taken the season-to-date lead among adults 18 to 49 with a 4.0 average rating, according to national Nielsen Media Research ratings. Former leader CBS has a 3.9 and continues to lead in total viewers.

That puts Fox in first place at an unusually early point in the season, a lead that network ratings analysts expect the network to maintain through the end of May.

Although Fox typically rises from fourth place to first during the spring, this is the first time in years that the presumptive season winner has taken the lead position this early.

During the past three years, the 18-to-49 race has been decided by a mere tenth of a rating point. Last year, the race between ABC and Fox went down to the last few days of the season, when Fox pulled out a victory.

The last time the winning network took the season-to-date lead this early was in 2003-04, when NBC was still powered by hits such as the final season of “Friends,” “ER,” the first season of “The Apprentice” and “Will and Grace.”

Among the runners-up, ABC has a 3.5, NBC has 3.4, Univision has a 1.6 and The CW a 1.3.

(Editor: Horowitz)