Clint Eastwood interviews an invisible Barack Obama

Clint Eastwood treated delegates at the Republican convention to an improvised performance were he showed off his acting skills by interviewing an invisible President Obama on an empty chair.

The Dirty Harry star flew into Tampa as a surprise last-minute speaker to warm the crowd up for Mitt Romney's acceptance speech.

The Associated Press is reporting that Romney aides backstage winced during the actor's performance, but assembled delegates cheered him on throughout.

Mr Eastwood declared of the incumbent president:

Inbetween sharing his views on the administration's foreign and financial policies, the 82-year-old turned to the empty chair several times through his speech to berate the invisible Obama:

The award-winning film director ad-libbed several lines from his long acting career:

President Obama responded on Twitter:

Despite Eastwood's Republican affiliation, many of his views differ with the party.

Although he has described himself as a fiscal conservative, he backs gay marriage, favors gun control and abortion rights and supports environmental causes.

The performance has already been depicted in Lego:

Minutes after the speech, the chair had its own Twitter account.