Amid the Jackson family's $40 billion wrongful death lawsuit against AEG Live, Conrad Murray -- who was sent to prison for the death of Michael Jackson -- is telling his side of the story.

Conrad Murray, the doctor convicted of involuntary manslaughter in the death of Michael Jackson, sounded a bizarre note during part of an interview with CNN's Anderson Cooper on Tuesday when he broke into song.

After talking to Cooper about the medication given to Jackson and expressing his desire to continue his "selfless acts of humanity," Murray then detailed some of the similarities he shared with Jackson.

"We had very, very humble lives, and we both experienced pain," Murray said in the segment, a jailhouse interview conducted via phone. "You know what describes me, Anderson? Let me sing something for you."

Murray then began to sing "The Little Boy That Santa Claus Forgot."

"He is a little boy that Santa Claus forgot and goodness knows he did not want a lot," Murray sang. "He wrote a note to Santa for some crayons and a toy. It broke his little heart when he found Santa hadn't come. In the streets he envied all the lucky boys, but goodness knows he didn't want a lot. I'm so sorry for that laddie who hasn't got a daddy, he's a little boy that Santa Claus forgot."

It was the first time someone "broke out into song during an interview with Anderson," Cooper's show noted.

"That song tells my story," Murray said. "That's how I grew up. I had no Christmases. I had no toys. I had nothing.... But as I grew up, my heart has been whole. And my heart says to help."

Murray is serving a four-year sentence for his 2011 conviction for involuntary manslaughter in Jackson's 2009 death. The verdict capped a seven-week trial during which prosecutors accused Murray of incompetence, saying he abandoned medical judgment by complying with Jackson's repeated requests for the surgical anesthetic propofol to help him sleep.

Witnesses testified that Murray chatted on the phone and sent emails and text messages as Jackson stopped breathing and suffered a heart attack while under the influence of propofol. Murray also delayed calling for help, they said, and lied to paramedics and emergency doctors.

Murray is appealing the conviction. He told Cooper that obstruction of justice had occurred.

He also said he hoped to get his medical license back so he could "set this aside" and "get back on the track where I can continue to help."

"I want to continue to contribute to humanity and this world in a very significant way," he told Cooper. "I want every young child, every mother and father, uncle and aunt, to satisfy dreams that they would have and goals they want to satisfy. I want to contribute to that."

Cooper also asked Murray about a lawsuit filed by Jackson's mother and children blaming entertainment giant AEG for his death, saying AEG negligently hired and supervised Murray and pushed Jackson to prepare for a tour he was not physically up to. Jury selection for that trial began Tuesday.

Murray told Cooper he had not been subpoenaed, but if he was, would invoke his 5th Amendment right to avoid "any issues of self-incrimination" in his own appeal.

When pressed further on the AEG lawsuit, Murray's attorney interjected, advising that her client not address the case. But Murray interrupted.

"There is one thing I'd like to say," he said. "I wish that one day I get a chance to tell all Michael's fans, people who really, really love him, what happened to Michael. They would really want to know and if they do find out, their heart would cringe and they would be in blatant pain."

When asked if he felt guilt in Jackson's death, Murray said he tried his best to save the singer and would have showed the "same valiant effort" were he a stranger.

"I have been a fan of Michael and I did everything when I discovered Michael, in his condition, to try to help him," Murray said. "I could have had a heart attack in my effort, but I did the best I can. I wholeheartedly tried."