The confirmation was revealed in a post from the show’s official UK Twitter account on Saturday, with the Suicide Squad star coming back to Ramsay Street for the final episode of the long-running Australian soap.
The 32-year-old played Donna Freedman on the show from 2008 to 2011.
Robbie’s return was announced alongside a number of other former stars, including House actor Jesse Spencer and singer Delta Goodrem.
Kym Valentine, who played Libby Kennedy, and Carla Bonner, who played Stephanie Scully, will also return.
After 37 years on screen, Neighbours will come to a close with a double-episode special on July 29.
Kylie Minogue’s Charlene Mitchell and Jason Donovan’s Scott Robinson had already been confirmed as returning for the finale.
Memento star Guy Pearce, who started his career playing Mike Young in the soap, is also reprising his role.
Joining them will be Peter O’Brien, who appeared in the show’s first episode as Shane Ramsay, as well as Ian Smith, who played Harold Bishop, Mark Little, who played Joe Mangel, and Paul Keane, who played Des Clarke.
Among those returning from the 2000s are Chris Milligan, who played Kyle Canning, Morgan Baker as Callum Rebecchi, Natalie Bassingthwaighte, who played Izzy Hoyland, and James Mason as Chris Pappas.
Neighbours executive producer Jason Herbison has told the BBC of how the show will finish: "I was really keen to have an ending that would be fulfilling, joyous and would be very Neighbours."
Neighbours will end with a double-episode special on Channel 5 at 9pm on July 29.