Mariah Carey, Ricky Martin, Tom Petty, Carlos Santana, Celine Dion and Shakira have joined Michael Jackson in asking "What More Can I Give" on a benefit single for September 11 relief efforts.

Also new to the lineup, according to an announcement from Jackson's publicist on Wednesday (October 17), are: Gloria Estefan, Usher, Julio Iglesias, Reba McEntire, Luther Vandross, Brian McKnight, Aaron Carter, Jon Secada, Billy Gilman, Boyz II Men's Shawn Stockman, Alejandro Sanz, Christian Castro, Olga Tañón, Juan Gabriel, Luis Miguel, Thalía, Ziggy Marley and 3LW.

Previously announced contributors include Destiny's Child, Backstreet Boys' Nick Carter and Mya. Lovebirds Britney Spears and Justin Timberlake were also named as participants when plans were first announced, but there was no mention of them in the latest update. A source close to the project said the two were never confirmed.

"What More Can I Give" will be released in both English and Spanish versions. It was unclear which artists will appear on which one. Jackson penned the song and is producing the English version, while KC Porter is overseeing production of the Spanish rendition. A release date has not been announced.

Jackson has been flying to studios around the country to record with the stars, according to his publicist. Santana recorded his guitar part in San Francisco with Porter last week, while other sessions have taken place in New York and Los Angeles.

The enigmatic pop legend has said he hopes the single will raise $50 million. "I believe in my heart that the music community will come together as one and rally to the aid of thousands of innocent victims," Jackson said in a statement. "There is a tremendous need for relief dollars right now, and through this effort each one of us can play an immediate role in helping comfort so many people."

In 1985, Jackson, Quincy Jones, Lionel Richie and Harry Belafonte led a group of artists in recording "We Are the World," which benefited famine-relief efforts in Ethiopia.

For more information on and audience reaction to the attacks, including tips on how you can help, see "9.11.01: Moving Forward."

Share your thoughts on the attacks in Afghanistan in You Tell Us.