Fonda, 75, has earned seven nominations and won Academy Awards for her roles in "Klute" and "Coming Home" in the past.
The veteran star, Garner, Stewart and Washington join a stellar list of previously announced Oscar presenters including Jennifer Aniston, Michael Douglas, Jamie Foxx, Paul Rudd, Salma Hayek Pinault, Melissa McCarthy, Liam Neeson, John Travolta, Ben Affleck, Jessica Chastain, Jennifer Lawrence, Halle Berry, Sandra Bullock and Nicole Kidman amongst many more.
Oscars will be presented on Sunday at the Dolby Theatre at Hollywood and Highland Center and will be hosted by Seth MacFarlane.