The project would launch on July 7, the day after the International Olympic Committee vote in Singapore to decide which city should host the event, reports the BBC.
Jowell said funding for the Olympics would come from three sources - the National Lottery, council tax payers in the capital and the London Development Agency.
Jowell said that although the bidding process had cost "millions, not billions," money had to be invested in the campaign.
"If you are going to do something like this, you have to commit money to doing it," she said.
