On Tuesday, Jermaine Jackson announced a list of artists scheduled to perform at a tribute concert for his brother, Michael Jackson, in Vienna, Austria, on Sept. 26, however several of the tribute's biggest artists are now denying involvement in the event.

The web site for the concert lists Chris Brown, Mary J. Blige, Akon, Natalie Cole, Sister Sledge and Angela Bassett as confirmed performers at the event, spokespeople for both Brown and Blige have released statements denying any such commitment.

According to the tribute's promoter, a Los Angeles judge was scheduled to give a ruling on Wednesday as to whether Brown would be allowed to travel to the tribute to perform, due to his recent sentence for assaulting former girlfriend Rihanna. However, a court spokesperson claims that no such overseas travel request has been made by Brown.

"Chris Brown is working out some situations, but he definitely expressed to us that he wants to be here, and it's just up to what he's going through with his court case right now, but he's definitely going to work that out and be here," Jermaine Jackson said in London on Wednesday.

Though Blige was unable to be reached for comment, the singer is said to be performing at a Gucci-sponsored concert in Milan, Italy on the date in question, and will thus unable to appear, according to an unnamed publicist.

Furthermore, while Natalie Cole's camp has stated that the singer is considering performing at the event, she has a potential conflict, and has not confirmed her appearance either.

Jackson responded to fan's concerns, claiming that Blige will be flying in to appear in the second half of the tribute, following her Milan performance, and that a slew of artists may also be confirmed shortly, including Stevie Wonder, R. Kelly and Maroon 5. Sounds fishy.