The global tribute for Michael Jackson set for September 26 in Vienna, Austria is still not certain to take place as an increasing number of singers will not perform.

Top singers including Chris Brown, Mary J Blige and Natalie Cole will not be there according to reports from TMZ.

Contrary to earlier reports of a family feud and Jackson's mother, Katherine, not approving the concert she released a video on Wednesday night pledging her support for the concert.

I am looking forward to being there, she said in a video recorded at around midnight on Wednesday in the library of the Jackson family compound in Los Angeles. I am sure it is going to be a great show. (Mrs Jackson in her video got the date wrong and said September 29 instead of September 26)

Negotiations are taking place with more than 50 TV networks to broadcast the spectacle to fans worldwide, event organizer said.

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