The 65-year-old action superstar, who stars in the first three instalments of the film franchise, said during promotion for his latest movie 'The Last Stand' that he will star in the forthcoming film, reported Sun Online.
Schwarzenegger is pleased with the direction the motion picture is taking after the film's bosses hired some "really quality writers".
"They're writing right now 'Terminator 5'. There have been some writers on it for the last year-and-a-half and they could not pull it off.
"We have told them over and over that they are going in the wrong direction, now they've finally got rid of those writers and they've got new really quality writers. Now they're going in the right direction. I think this year the script will be finished and we will be able to go into pre-production," he said.