"It will be a positive ad about the things I will do if I were president. It's contrasting with the president's ad, which came out, once again, as a character assassination ad," he said in Florida.

The ad will run in Iowa, Ohio, North Carolina and Virginia, according to NBC news, four swing states that are key to Romney's reelection. The ad buy is for $1.3 million, a relatively small purchase spread over the states.