Actress Jennifer Aniston is returning to the small screen with a guest spot on NBC's 30 Rock . "She is shooting now," her rep, Steven Huvane, confirmed to E! Online . "We are not giving out any specifics on her character." The episode is slated to air this season. Aniston's former Friends co-star David Schwimmer has also appeared on 30 Rock . See photos of Jennifer Aniston's 39 years of love and drama . Aniston -- who split with John Mayer earlier this month -- has previously ...