Jack Black used to think he was a bad actor.

The 52-year-old movie star has enjoyed a decades-long career in Hollywood starring in hits such as 'School of Rock' and 'Nacho Libre' but admitted when he first started out he thought he was "horrible" until he saw the final cut in cinemas.

He said: "I remember the first movie I ever did. I saw a rough cut, and I was like, “Oh, my god, I’m a bad actor. I’m horrible.” And then, the editor just did some magic, and by the end, when it was released in theatres, I was like, “Oh, my god, I’m fantastic. I’m fantastic at acting!'"

The 'Kung Fu Panda' star went on to explain that it was all "magic" done in post-production and claimed that editors don't get the credit they deserve.

He told Collider: "The editor trims away all the fat, which is a crucial job. People don’t celebrate the editor!"

Meanwhile, Jack admitted that even though it would be "cool" to step behind the camera and become a director, he prefers to be the one "putting on a show."

He said: "At the end of the day, I like putting on a show. I don’t know that I’d like to be a director. It would be cool to be a director, just because of the respect that you get. It would be cool to be Paul Thomas Anderson or Taika Waititi, where people look up to you and respect you. But I don’t know if I really want the job."