UFC officials announced the 170-pound non-title bout on Wednesday. UFC 219 will take place inside T-Mobile Arena in Las Vegas.
Condit (30-10) hasn't fought since a first-round submission loss to Demian Maia in August 2016. A longtime fan favorite, Condit had discussed retirement following the defeat; but he announced last month his intention to return to action.
Fighting out of Jackson-Wink MMA in Albuquerque, New Mexico, Condit challenged Robbie Lawler for the UFC championship in January 2016. He came up short via split decision.
Magny (19-6), fighting out of Denver, is coming off a submission loss to Rafael dos Anjos in September. He is 1-2 in his past three fights.
The UFC has not yet announced a main event for the UFC 219 pay-per-view competition.