CBS News correspondent Bob Schieffer was caught off guard Sunday when he made an instant cameo in a Romney campaign commercial airing during his own program.

In the commercial, Schieffer -- who hosts CBS' "Face the Nation" -- was shown questioning Obama campaign adviser David Axelrod over a barrage of negative ads, especially attacks on presumptive Republican presidential nominee Mitt Romney and Bain Capital.

"Whatever happened to hope and change?" the spot showed Schieffer saying in footage from the program.

Schieffer opened a later segment saying he was "shocked" by the ad and distancing himself from it.

"That was a question that I posed to David Axelrod -- not a statement," he said. "I have no affiliation with the Romney campaign. This was done without our permission."

Schieffer noted the precarious position of an independent journalist appearing in a campaign ad: "I'm sure I'll get some blowback."

(Also on POLITICO: Ed Gillespie says Bain attacks are 'working')