Janet Jackson's 'no' to tribute concert.

Janet Jackson's turned down the chance to headline the Michael Jackson tribute concert in Cardiff in October.

Janet says it's because the date coincides with the involuntary manslaughter trial of the doctor accused of administering the drug that killed her brother.

In a statement released on what would have been Michael's 53rd birthday, she says, "Because of the trial, the timing of this tribute to our brother would be too difficult for me."

Dr. Conrad Murray's trial is scheduled to begin in Los Angeles at the end of September. Murray has pleaded not guilty to all charges against him.

The Michael Forever -  Tribute Concert will feature JLS, Alexandra Burke, Christina Aguilera, Cee Lo Green and mum to be Beyonce is expected to put in an appearance via the video screens.