Media playback is unsupported on your device Media caption Clint Eastwood tells Barack Obama "you can still use the plane"

Actor Clint Eastwood has defended his widely mocked appearance at the Republican National Convention, saying criticism has come "from the left".

The 82-year-old conducted an imaginary conversation with Barack Obama at the convention, where he was endorsing Presidential candidate Mitt Romney.

Speaking to California newspaper The Pine Cone, he said the idea had come to him at the last minute.

He admitted it was "unorthodox" but called the crowd "super enthusiastic".

"I may have irritated a lot of the lefties but I was aiming for people in the middle," Eastwood told the newspaper, which serves the California town of Carmel where he served as mayor in the 1980s.

The rambling speech drew widespread criticism, with some commentators saying it had damaged Romney's campaign.

Eastwood addressed an empty chair, asking: "Mr President, how do you handle promises that you have made when you were running for election, and how do you handle them? I mean, what do you say to people?"

Later he concluded: "When somebody doesn't do the job, you gotta let 'em go," before drawing a finger across his throat.

'Joe citizen'

MSNBC news presenter Rachel Maddow seemed to be lost for words immediately after the speech. "I don't know what was going on there," she told viewers.

"Clint Eastwood is 82 years old and I think that... I don't know if that's what was going on there."

Image caption President Obama responded to the speech by posting this picture on Twitter

CNN host Howard Kurtz called it the "weirdest convention moment I have ever seen".

According to the New York Times, even Republican Party advisers called the 12-minute address "strange" and "weird".

Eastwood, star of Unforgiven and the Dirty Harry films, was unabashed by the reaction.

"It was supposed to be a contrast with all the scripted speeches because I'm Joe Citizen," he said.

"I'm a movie maker, but I have the same feelings as the average guy out there."

The Oscar-winning director said campaign aides had asked for details about his speech in advance. "But I told them, 'You can't do that with me, because I don't know what I'm going to say.'"

The idea to deliver a speech to an invisible Obama only came to him 15 minutes before he stepped out on the stage in Tampa, Florida.

"There was a stool there, and some fella kept asking me if I wanted to sit down," Eastwood said. "When I saw the stool sitting there, it gave me the idea.

"I'll just put the stool out there, and I'll talk to Mr Obama and ask him why he didn't keep all of the promises he made to everybody."

Following the speech, President Obama tweeted of himself seated in the a chair labelled 'The President', saying: "This seat's taken."

The President had his own celebrity endorsers at the Democratic National Convention, which took place last week in Charlotte, North Carolina.

Actress Scarlett Johansson, singer James Taylor and Eva Longoria of Desperate Housewives fame were among those to speak in support of the commander in chief.