Andretti Autosport will join forces with Harding Steinbrenner Racing via a partnership that means the former will field a fifth entry in the 2020 IndyCar season for Colton Herta.
Herta became the youngest ever IndyCar winner with victory at Austin back in March, and he also scored poles at Road America and Portland.
The #88 Honda-powered entry will race under the Andretti Harding Steinbrenner Autosport banner for 2020, with current HSR team principals Mike Harding and George Michael Steinbrenner IV joining Michael Andretti as 'leadership partners'.
This formalises the relationship between the Andretti Autosport and Harding Steinbrenner teams that led to them sharing all data and debriefing together this year.
Key Andretti Autosport engineers such as Nathan O'Rourke and Andy Listes have been working at Harding Steinbrenner.
Herta had been courted by the Arrow McLaren Racing SP squad, as the Sam Schmidt/Ric Peterson-owned team will be known next year, for a possible 2020 drive.
But Andretti had an option on Herta provided he could supply a guaranteed ride, and this deal has now been completed.
Herta will join Alexander Rossi, Ryan Hunter-Reay, Marco Andretti and Zach Veach for the 2020 season.