Arnold Schwarzenegger has admitted he had no idea his Terminator line "I'll be back" would become so big.

The action star first uttered the words in the 1984 sci-fi film and the sentence has gone on to become his best known catchphrase.

But the 66-year-old, who is reprising his cyborg role in the upcoming Terminator: Genesis, told The Sunday Times: "When I said 'I'll be back', I didn't have the foggiest idea that it would become the most quoted line in movie history.

"I think it's just how you say it. Like the line, 'Get to the chopper.' I sometimes visit a university to do a speech and people are screaming, 'Get to the chooopper!' and then they ask me to say that in the microphone, in my way, with my accent. I mean, what's funny about that?'."

The Austrian-American star revealed he used to be told his accent would hold him back in the movie industry.

Arnie explained: "When I wanted to go from body-building into the movie business, the thing that agents and studio executives always told me was, 'You will never, ever become a leading man because of your accent.'

"But I didn't accept that. As Nelson Mandela said, 'It always seems impossible until it's done.' I made it possible."