Publicist Stephen Huvane told E! Online exclusively Friday that the actress will appear on the popular NBC sitcom this season, marking her first return to an NBC series since "Friends" went off the air in 2004.
"She is shooting now," Huvane said. "We are not giving any specifics on her character."
The news of Aniston's guest appearance on "Rock" comes in the wake of news that Emmy nominee and former "Arrested Development" star Will Arnett will remain with the sitcom.
E! Online said Aniston's appearance on the show marks the second time a "Friends" star has lent their comedic skills to "Rock." Her former co-star David Schwimmer had a guest spot on "Rock" last season.
The season premiere of "30 Rock" is set for Oct. 30.