The prize presentation is to take place Nov. 22 at the NOKIA Theatre L.A. LIVE. It is to be broadcast live on ABC.
Dick Clark Productions President Orly Adelson said Tuesday Jay-Z will join the previously announced Keys in a collaborative act.
The lineup of other artists set to perform includes The Black Eyed Peas, Jennifer Lopez and Adam Lambert.
Additional performers and presenters will be announced in the coming weeks, ABC said in a news release.
"We are thrilled to have Jay-Z and Alicia Keys on stage together for the 2009 American Music Awards," AMA producer Larry Klein said in a statement. "Both are such talented artists, it's sure to be a memorable performance."