Jo, played by Katy Manning, will join fellow former sidekick Sarah Jane Smith and the Doctor in two episodes of the new series on CBBC this autumn.
Pin-up Jo was a companion of the third incarnation of the Doctor, played by Jon Pertwee, in the 1970s.
The feisty character fell in love with eco-warrior Professor Clifford Jones and left the Doctor to explore the Amazon with her new fiance.
Katy caused a stir in real life 30 years ago when she stripped off to pose for pictures with a Dalek. Matt follows in the footsteps of David Tennant, who also appeared as the Time Lord in the Doctor Who spin-off last year.
Elisabeth Sladen, who plays Sarah Jane, said: "It's a fantastic script and I can't wait to work with another Doctor and hope Matt has fun with us. I've known Katy for ages and I am delighted to be working with her."
Executive producer Nikki Wilson said: "We are absolutely thrilled to be introducing Sarah Jane and the gang to both the 11th Doctor and Jo Grant, and to have a script penned by Russell T Davies is the icing on the cake!"
Guest stars are lined up to appear in the series include former Strictly Come Dancing contestant Laila Rouass and David Bradley, who played Argus Filch in Harry Potter, providing the voice of the Shansheeth.