Michael Jackson was "cracking up" under the pressure of his 50 London shows, according to a psychiatrist.

The unnamed analyst claims the late pop icon was increasingly erratic ahead of the proposed dates, which were due to start in July and run into 2010, with him veering between "almost manic" excitement before lapsing into silence and staring into space.

According to a source, the psychiatrist - who met with Jackson twice, the second time on June 12, just weeks before his death - said the singer was "clearly not mentally or physically equipped to cope" with the planned comeback.

The source added to Britain's The Sun newspaper: "Michael was always adamant the show must go on - to the point where he was obsessed with the idea he would be 'killed' if he couldn't go on stage.

"He had been backed into a corner and was falling apart under the strain."

The psychiatrist had told the 'Bad' hitmaker's other doctors, including skin specialist Arnold Klein, he had a "deep concern" for Jackson, who was also obsessed with his skin condition vitiligo.

Jackson's fragile mental state was also manifesting itself in "punishing and controlling behaviour" and a desire to sabotage aspects of his professional life.

The source added: "Michael had been candid at their first meeting, but showed clear signs of cracking up when he saw him again."

Meanwhile, footage of Jackson's final rehearsal concert is being tipped to win an Oscar.

The recordings of the singer's final rehearsals are to be released with an accompanying feature length documentary, and are said to include his last ever Moonwalk - his trademark dance move - as well as three new music videos and an enhanced version of his biggest hit 'Thriller'.

Those who have seen a sneak preview of the material are confident it could earn Michael a posthumous Academy Award.