Republicans on Twitter dubbed Monday “National Empty Chair Day,” playing up actor Clint Eastwood’s speech at the GOP convention last week and mocking President Obama.

Twitter users tweeted photos of empty chairs in different settings with the hashtag #emptychairday in homage to Eastwood, who brought a chair on stage and addressed it as “Mr. Obama.”

In the 10-minute ad-libbed speech delivered in Tampa, Fla., on Thursday, Eastwood pretended to ask questions of an invisible Obama seated in the chair.

The performance sparked a Twitter firestorm, with many calling it bizarre and inappropriate and others treating it as a humorous skit.

The Obama campaign quickly ribbed Eastwood, whom many Republicans feared stole attention from Mitt Romney’s acceptance speech that night.

“We’re all Clint Eastwood fans here in the Obama campaign,” senior adviser David Plouffe said on Sunday.