Michael Jackson Overexerted Himself in Tour Rehearsal, Insiders Say

July 2, 2009— -- Poised for the so-called comeback shows of his career, Michael Jackson rehearsed tirelessly in his final days -- at times overexerting himself in rehearsals, insiders tell ABC News.

Jackson's death June 25 came before the start of his upcoming "This Is It" concerts, which would have amounted to his first major concert series since his HIStory tour that ended in 1997.

The 50-year-old Jackson was scheduled to perform 50 sold-out concerts at London's O2 Arena, promoted by AEG Live, from July 13 to March 6, 2010.

"I think he had a sense of timing that this was the time to do it," AEG Live CEO Randy Phillips said in an interview with ABC News' Chris Connelly. "He was always negotiating and renegotiating. And he was a character. He was our character."

Phillips said that the 50 scheduled performances were not too many to be contractually expected of Jackson.

"We're talking about 50 shows in one city -- no travel, living in a beautiful estate outside of London," Phillips said. "He was going to average two-and-a-quarter shows a week. You can't do less than that and spend this much money on production and advertise it ... and make money.

"This was his chance also to get his finances in order," Phillips added.

Those who watched Jackson perform were convinced that he was healthy enough to tour. Before the tour's formal announcement, Phillips said, Jackson was given a five-hour medical examination by Dr. David Slavik, in which Jackson was given a "clean bill of health."

Phillips said that Jackson insisted that AEG hire his doctor of choice, Dr. Conrad Murray, the Houston- and Las Vegas-based physician who was with Jackson as he died, for 24-hour medical assistance on tour in London. AEG was paying Murray $150,000 per month for compensatory fees, as well as hotel and travel costs.

When Phillips attempted to contest the "ungodly" costs of retaining Murray, Jackson pushed back.

"Michael looked me in the eye, and he's strong and he was stubborn and wanted something," Phillips said. "He looked me in the eye [and said], 'Look, this is the machine,' pointing to his body, 'that fuels this entire business. OK? I need a doctor 24/7. He's my doctor. I am comfortable with him, he's an incredible guy and he makes me feel good about myself.'"