US presidential candidate Barack Obama is set to air a 30-minute prime-time election advert on leading American TV networks tonight as part of his campaign for the White House.
The move is believed to have cost the Democratic candidate between $3m and $5m.
Obama has been able to easily outspend his Republican rival John McCain during the presidential campaign after setting new records for election fund-raising in the US.
He is ahead of McCain in the opinion polls ahead of the election next Tuesday.
At 8pm, American Eastern time on, Obama will be broadcasting simultaneously on NBC, Fox and CBS.
The Obama campaign asked CNN to air its 30-minute campaign ad, scheduled for Wednesday evening, but the network turned them down.
“CNN was approached by the Obama campaign and declined their request,” the network said in a Tuesday statement. “We did not want to pre-empt our programming lineup with a 30-minute campaign commercial. We prefer to use our air to continue to cover the campaign, candidates and issues like we always do from all points of view with the best political team on television.”
Fox News Channel – which is a separate network from FOX - was not asked to air the ad.