Sources at media buying agencies suggest that 30-second advertising spots during the two-hour live show and half-hour results programme on Saturday are being snapped up for £120,000 each, reports Media Week.
Britain's Got Talent's main sponsor is price comparison website MoneySupermarket.com, while Sky Broadband, Wall's Sausages and TheTrainline.com are among the brands due to advertise in the final.
The talent show has been boosted this week by the return of Simon Cowell, after he stepped back to concentrate on the launch of The X Factor USA. Cowell's Syco TV outfit also co-produces Britain's Got Talent with RTL's FremantleMedia.
On Monday, Cowell's return for the first Britain's Got Talent semi-final helped the show average 10.91 million viewers for ITV1 in primetime, commanding 41.9% of the audience.
Despite the 2011 crop of artists on Britain's Got Talent possibly lacking the sparkle of previous series, a media agency source said that the show was still a powerful platform for brands.
"Getting into the final has not been the fight it has been in the past but it's still the biggest thing on TV at the moment," said the source.
ITV's revenue windfall from the Britain's Got Talent final follows the more-than £8m earned by the broadcaster from last weekend's UEFA Champions League final.
However, the commercial broadcaster is facing a tough summer ahead in the advertising market, with revenues in June expected to be down by as much as 20% year-on-year.