U2 freebie rakes in $US3 million for AIDS

Rock group U2's new single Invisible raised more than $US3 million ($A3.4 million) for the fight against AIDS during the 36 hours it was available for free on iTunes.

It scored more than one million downloads in the hour after it premiered in a Bank of America commercial during Sunday's Super Bowl, then picked up two million more until the free offer ended.

With the second-biggest bank in the United States pledging one dollar for every download, Invisible raised more than $US3 million for the Global Fund to Fight AIDS, Tuberculosis and Malaria.

The song now is selling on iTunes for $US1.29 with all proceeds going to the Global Fund, said (RED), a charity co-founded in 2006 by U2 frontman Bono to engage big consumer brands in AIDS fund-raising, in a statement.

"We are very thrilled with this, Invisible, it sounds great and it feels good," Bono told Britain's BBC Radio One pop music station on Monday.

"We're just delighted there are still people very interested in us."

The Bank of America, which made $US3.4 billion last year, has committed $US10 million over two years to fight AIDS in a partnership with (RED) and U2.