Romney adviser: Eastwood a 'great messenger'

New Orleans, Louisiana (CNN) – When iconic actor and Romney supporter Clint Eastwood asked for a chair to be brought onto the convention stage Thursday night, staffers did not realize it would become an integral part of his speech, according to a senior aide.

Eastwood's performance on-stage - largely a conversation between the actor and the empty chair he used to symbolize President Obama - raised eyebrows and quickly went viral, as thousands of viewers tweeted bemused reactions to the unconventional remarks.

- Follow the Ticker on Twitter: @PoliticalTicker

- Check out the CNN Electoral Map and Calculator and game out your own strategy for November.

Romney staffers were not privy to an advance copy of Eastwood's speech – in fact, he ad-libbed his endorsement of the Republican nominee, the adviser said.

Eastwood previously endorsed Romney at a campaign fund-raiser, but news cameras were not allowed to film the revered tough-guy movie star's appearance with Romney.

So the campaign made Eastwood a surprise guest Thursday night, on the final evening of a minutely-orchestrated convention carefully designed to introduce Romney to millions of voters.

However, Eastwood's remarks do not appear to have been subject to that level of scrutiny.

Senior strategist Stuart Stevens called Eastwood's use of the chair "improv" but shrugged off concerns the unexpected speech could distract from Romney's message.

"The crowd loved it," Stevens said, adding that Romney had been backstage laughing along with the audience. "He thought it was funny."

"For him to go out there and to say that there's a need to change presidents and that he supports Mitt Romney, and talk about 23 million people out of work as he did, and talk about when someone doesn't do their job you need to change, that's a powerful message," Stevens said. "He's a great messenger. The guy is an American treasure."