Madonna is expected to pop up and lend guest vocals during a performance from one of the night’s nominees, an additional source confirmed.
The list of this year’s Grammy performers includes Paul McCartney and Ringo Starr; Daft Punk with Nile Rodgers, Pharrell Williams and Stevie Wonder; Kendrick Lamar with Imagine Dragons; Lorde; Katy Perry; Pink and Fun’s Nate Ruess; Robin Thicke and Chicago; Macklemore & Ryan Lewis; Kacey Musgraves; John Legend; Taylor Swift; Keith Urban and Merle Haggard, Kris Kristofferson, Willie Nelson and Blake Shelton.
The Grammy awards are on January 26th.

Los Angeles Times