Mitt Romney filmed a campaign ad in Iowa

When Mitt Romney visited Iowa earlier this week, he campaigned in front of an enormous steel sign carved into the shape of Iowa and stamped with his campaign's 2012 logo.

It turns out the sign was a prop set, and will be featured in a campaign ad Romney shot during his stop at a Dubuque sheet metal plant—yet another indication that the former Massachusetts governor is increasing his political presence in the state ahead of its Jan. 3 caucuses.

Romney aides aren't talking about the ad, which was first reported by the Associated Press. But the move isn't surprising, given recent polls in the state show Romney remains popular in Iowa--even though he's campaigned there just four times this year.

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