Howard Stern thought about quitting his radio show when his $500 million five-year contract was up for renewal.

The 57-year-old shock jock was tempted to retire last year because he thought he was a "horrible host" - but in the end signed on the dotted line to continue working with US station Sirius XM Radio because of a "neurotic compulsion".

He said: "I came to a conclusion. My contract was up a few months ago. I really thought I was going to retire. I said, 'Why am I doing this anymore? I've proven everything I needed to prove. It makes me crazy.

"I hate getting up early every morning... I am driven by a neurotic compulsion to do that show. And it doesn't seem enjoyable. I go home every night and go, 'I did a horrible job!'"

Speaking to TV talk show host Piers Morgan he said that being a radio DJ was his "identity" and "ego".

He wouldn't reveal the exact figure his new deal with the station is worth but did admit that it was "a little more for a little less work".