Rock was arrested by Vegas police and charged with misdemeanor battery for the incident.
"It's been going on for five years," Rock said of the tension between him and Lee, both of whom were married to actress Pamela Anderson.
"I did what any man would do, any man across the country, across the world would do," he said, adding, "It kills me just to be associated with, to have my name in a sentence with him; it honestly destroys me."
Rock made the remarks on Thursday morning's The Kevin & Bean Show on Los Angeles' KROQ-FM.
The singer said the last time he had contact with Lee was when Rock was in the midst of his divorce from Anderson.
"He picked up her Blackberry and started e-mailing me a lot of horrendous things. It was extremely disrespectful," Rock recalled, maintaining the smack-down in Vegas was "unavoidable."
"I had to do what I had to do because this was a long time coming. ... I came back from the bathroom and he was sitting right there. It was even more disrespectful after everything he's said. I was like, 'That's enough.'"
Anderson was reportedly sitting on Lee’s lap shortly before the brush-up.