He will partner Thierry Neuville and Dani Sordo at next month’s RallyRACC Catalunya - Rally de España (5 - 8 October), with Hayden Paddon dropped for the mixed surface encounter.
Hyundai said its line-up for Dayinsure Wales Rally GB (26 - 29 October) and Kennards Hire Rally Australia (16 - 19 November) would differ from Spain, but did not provide details.
It is likely Paddon will return, with Sordo missing out. Team principal Michel Nandan acknowledged the decision to make changes was not easy, but necessary in an effort to rekindle its manufacturers’ title hopes. Hyundai trails M-Sport World Rally Team by 64 points after poor performances at the most recent rounds in Finland and Germany.
Mikkelsen lost his full-time seat when Volkswagen Motorsport left the WRC at the end of 2016. He tested with Hyundai in Portugal in April, but speculation he would join its line-up soon after came to nothing.
Instead he joined the Citroën Total Abu Dhabi squad, ushering in several updates to the troubled C3 car and driving three rallies, culminating in second place at last month’s ADAC Rallye Deutschland.
It is believed that Mikkelsen joining Hyundai for the final three rounds was conditional on being offered a longer-term deal for next season.