Emerging from a London rehab clinic where she has spent the past two weeks, Amy Winehouse is set to perform during the Grammy Awards on Sunday night, but she won't be in the building.

The acclaimed but troubled singer had her request for a US visa denied this week by the American Embassy in London, a decision that surprised few in the wake of the singer's public struggles with drug addiction.

Winehouse was questioned by detectives from London's Metropolitan Police on Tuesday about a video that allegedly showed her smoking crack cocaine. The publication of the video by UK tabloid The Sun last month resulted in Winehouse heading to rehab once again.

But Winehouse will perform during the ceremony via satellite. "I'm raring to go and really excited to be performing at my first Grammy Awards," Winehouse said in a statement issued Friday. "I'd like to thank everyone for their support over the last couple of weeks. I'm really sorry I can't be there but I appreciate that I'm being given a second chance via satellite."

Winehouse will remain under medical supervision, and her treatment will continue following the performance. Winehouse is up for six Grammys: record of the year, song of the year, and best female pop vocal performance for "Rehab;" album of the year; and best pop vocal album for Back to Black, as well as best new artist.

But though Winehouse won't be at the Staples Center in Los Angeles for the ceremony as her label had hoped, plenty of music's biggest stars will, including Kanye West, the only artist to garner more nominations, at eight, than Winehouse.

West was announced as a performer at the ceremony today, and will likely do a two-song set that will include "Stronger," which was nominated for best rap solo performance, and "Hey Mama" from his sophomore effort, Late Registration. The latter will be a tribute to West's mother, Donda West, who died Nov. 10.

Grammy organizers are promising a number of collaborative performances, including Beyoncé with Tina Turner; Fergie and John Legend; and Josh Groban and Andrea Bocelli. John Fogerty, who is nominated for best rock album for Revival, will be performing with rock legends Little Richard and Jerry Lee Lewis in a "Cornerstones of Rock" segment during the 50th annual event.

In addition, jazz legend Herbie Hancock will play with Chinese piano prodigy Lang Lang, a fellow Grammy nominee. Kid Rock, pianist Eldar, saxophonist Dave Koz, and singer Keely Smith were also added to the list of performers.

As previously announced, Aretha Franklin and Mary J. Blige will be part of a huge gospel tribute, and Beyoncé, Feist, Alicia Keys, Brad Paisley, and Carrie Underwood are also set to perform.

The My Grammy Moment performance will feature the Foo Fighters performing "The Pretender" joined by an orchestra that will include three aspiring instrumentalists picked by viewers, and conducted by Led Zeppelin bassist John Paul Jones.

The Recording Academy also unveiled a new batch of presenters for the ceremony, including Chris Brown, Miley Cyrus, Akon, Tony Bennett, Cher, Nelly Furtado, Quincy Jones, Prince, Ringo Starr, Dave Stewart, Taylor Swift, Stevie Wonder, Tom Hanks, Joe Mantegna, Jason Bateman, Solange Knowles, George Lopez, Lyle Lovett, and Ludacris.

The 50th annual Grammy Awards will be broadcast on CBS 8-11:30pm ET/PT.