Arnold Schwarzenegger denies the cash he gave to the mother of his love child was "hush money".

The Hollywood legend had an affair with his housekeeper Mildred Baena and fathered a boy called Joseph. Arnold speaks about his infidelity in his new memoir Total Recall: My Unbelievably True Life Story, and promoted the book in an interview for US TV show 60 Minutes.

The star refused to reveal how he found out he had a son with Mildred, claiming he just "put things together".

Arnold started sending Mildred sums of money in secret, and she never questioned why.

The 65-year-old insists she "knew what it was about", but is adamant that the payments were not made for her silence.

"Mildred is a good person. She was not out to get me or take advantage of me," he explained.

The former politician showed remorse for his illicit relationship.

"I think it was the stupidest thing I've done in the whole relationship. It was terrible. I inflicted tremendous pain [on my family]," he said.

Arnold kept other secrets during his 25-year marriage to Maria Shriver.

The star hid the fact that he had major heart surgery from his wife because she was pregnant at the time. He also only told Maria he was planning to run for governor of California a few days before he submitted his application.

"I didn't want endless conversation about it at home," he confessed, before recalling the moment he told her. "She started shaking. And she had tears in her eyes. I realise that I was stepping into something that was much deeper than just me running and her being a supportive wife

"That's the way I handle things. And it always has worked. But it's not the best thing for people around me because some information I just keep to myself."

In the new book Arnold also confirms that he had an affair with actress Brigitte Nielsen during his marriage to Maria.