Via Dan Riehl and Ace, you already sort of knew this but now you really sort of know it:

Officials confirmed Wednesday that a surprise guest was still on the schedule but declined further comment.

One Republican source told FoxNews.com that Eastwood is indeed the mystery speaker, following an online report that claimed the actor is planning to travel to Tampa for the convention.

If the Academy Award winner is the one, he could get a mixed reception with the Hollywood-leery crowd.

“He’s all right, despite being associated with Hollywood,” Bruce Thompson, a California delegate, said laconically. “He’s a good guy and was a good mayor.”

C’mon. Does anyone think Clint Eastwood, who’s been a libertarian-leaning Republican for decades on top of being an international symbol of American western badass-ery, isn’t going to be received rapturously? Romney will have an honest-to-goodness liberal Democrat speaking on his behalf tonight too and she’ll also be well received, just as Zell Miller and Artur Davis were. As long as you’re helping to beat the Democrat, all is forgiven. (Just ask John McCain.) If anything, Eastwood will be more appreciated because he comes from Hollywood, because he’s willing to stand up to the ideological orthodoxy of his industry on a huge stage. And he’s esteemed enough by his peers that he’ll get away with it.

Further circumstantial evidence that it’s Eastwood, posted yesterday on Twitter:

I actually know who the mystery speaker is tonight. Like, for real. Kinda bummed about it, too.

— Patton Oswalt (@pattonoswalt) August 29, 2012

Oswalt’s an actor, comedian, and outspoken liberal. Can’t imagine why he’d have inside info on a mystery speaker at the GOP convention unless it’s someone from his own field and he’s hearing it through the Hollywood grapevine. And the only reason that he’d be disappointed is if that guy was sufficiently respected in entertainment that a liberal would be sad to see him on the other team. All of that points right to Clint.

One other possibility, though: What if Eastwood’s going to speak as a last-minute addition, but he’s not actually the “mystery speaker”? Last night after Palin announced on Facebook that her Wednesday evening segments had all been canceled by Fox News, Ed e-mailed me wondering if they might have done that because they found out she’s the mystery speaker. After all, they wouldn’t want her commenting on air on an event that she’s soon to participate in. Fox’s excuse last night for pulling her was that they had to scramble to compress their schedule once the convention shrank from four days to three, but that makes no sense. If you’re going to bump people off the air, you’re not going to bump someone with Palin’s star power instead of a lesser-known Fox News analyst. And if you’re intent on bumping Palin, why on earth would you bump her last night instead of Tuesday? McCain spoke last night, as did her successor as VP nominee. If there’s any night you’d want her on air to react, last night was it. Either it’s bad programming by Fox or there’s more going on here.

Update: Romney pal Paul Gilbert says yes, it’s Eastwood. 100 percent sure.