Questions about Michael Jackson's health have dominated conversations about the pop icon since his unexpected death last week from cardiac arrest.
But the singer's trainer, actor and bodybuilder Lou Ferrigno, said Jackson was "in fantastic shape."
"He might have been a little thin because he was under a lot of stress training for the tour," Ferrigno, who played the Hulk in "The Incredible Hulk" TV series, said in an interview that aired on "Good Morning America" today. "But when I put him through the routine and everything, I mean, it was just fine. I mean, very energetic."
He said Jackson could have handled his tour, which was scheduled to begin next month.
"He was dancing as good as anyone. And, you know, I'm an expert. And I was with Michael. If I didn't feel Michael could've pulled this off, I would've told him," Ferrigno said. "I think he was going to give the greatest tour in his entire life."
Ferrigno's assessment of Jackson's physical condition stands in stark contrast to one writer's description of the Gary, Ind., native.
Ian Halperin, who is publishing a new biography on the "Thriller" singer, wrote in December that Jackson had only six months to live. He said Jackson suffered from a rare form of lung disorder.
"On some days, he could barely talk," Halperin wrote recently in a British publication. "He could no longer dance."
Halperin said it would have been impossible for the father of three to complete one concert, much less the 50 he had planned.
Halperin, whose book, "Unmasked: The Final Years of Michael Jackson," is due for release in late July, said the former Jackson 5 lead singer was suicidal on some days.
The singer's representatives have denied claims that Jackson's health was on the decline, saying the "moon-walker" passed a four-hour physical in preparation for his London concerts.
Ferrigno, who has known Jackson for 15 years, said the pop icon was "very energetic" during workouts and "was in fantastic shape," although "he might have been a little thin because he was under a lot of stress training for the tour."
Ferrigno, 57, said he last trained with Jackson, 50, about three weeks and would go to the singer's home three or four times a week.
The two used tools like exercise balls and did a lot of core training to get Jackson in shape.
"He didn't want to weight train. So he mostly wanted to deal with flexibility and conditioning," Ferrigno said. "He didn't look like he was in pain because he was on the treadmill. He did the stretching exercises."
In addition to training, it seems that Jackson kept a strict diet.
"I think he was a vegetarian. And he only ate once a day. But I just told him the proper supplements to take," Ferrigno said. "The most important thing was the attitude, the mind because he really wanted to be in his best shape."
According to lighting designer Patrick Woodroffe, Jackson didn't always appear in peak condition during rehearsals for his upcoming tour.
"The sense in the camp was that we were nervous. We were nervous about whether we would be able to pull off the show," he said in a BBC radio interview.
The singer would often miss rehearsals, said Woodroffe, who watched Jackson rehearse two days before he died.
But his final rehearsal began to change the view of the crew.
"He was frail, you might say, but something seemed to happen over the weekend, and he came into rehearsal on Tuesday and something really extraordinary seemed to happen. He came on stage at 9 in the evening and we all looked at each other and it was something that said he really had it," Woodroffe said.
Woodroffe said the artist was performing extremely well.
"Suddenly, he was performing as one had remembered him in the past, and he was singing. A lot of the times the director and engineers will say, 'Hold your voice. Don't sing out,' and it was almost like he couldn't stop himself," Woodroffe said.
But by the end of the run-through, Woodroffe said workers believed Jackson could pull of the hectic concert schedule.
"We all had a view as to whether he would be able to survive these 50 shows and whether he could have. I couldn't tell you, but I can certainly tell you he would have made it to the start of the race if you know what I mean," he said. "Whatever the view of Michael Jackson is, there's this sense that he would have done it and that was exciting.'
The King of Pop has struggled with his health since 1984 when he became addicted to painkillers after receiving severe burns filming a Pepsi commercial. The pop star's hair caught fire, leaving Jackson in excruciating pain.
A former family lawyer told "GMA" he knew Jackson had a drug problem.
"I spoke to family members. I said to them, If this situation arises where Michael perishes because of medications, and my words were, 'If he one day wakes up and he's dead because of these medications, I will not hold my tongue. I will speak out and I will speak out loud,'" said former family attorney Brian Oxman.
In 1995, Jackson collapsed while rehearsing for a television special. His doctors said he fainted because of an abnormal heart rhythm caused by dehydration.
Jackson had an anxiety attack at a copyright lawsuit court appearance and was treated with intravenous fluids and tranquillizers in 2003.