Hit talent show American Idol now has a price tag the size of Simon Cowell's ego

The American Idol franchise has been valued at a staggering $2.5b by industry magazine Advertising Age.

The magazine came up with the figure by adding Idol's $500m advertising deals, its sponsorship packages worth $30m to $50m, and its music sales and live tours.

And industry experts did not even factor in Idol chocolate bars, ice cream and a Monopoly game, which are currently under consideration.

Season Six of the show returns to American TV screens next week. Last season's finale was watched by 36m viewers.