Indianapolis 500 winner Takuma Sato will return to Rahal Letterman Lanigan Racing for the 2018 IndyCar season.
Ex-Formula 1 driver Sato moves across to Rahal after a single season at the Andretti Autosport squad.
Sato scored four top-five finishes during the 2017 season, including the first-ever Indy 500 win for a Japanese driver, and ended the year a career-best eighth place in the standings.
But the delay in Andretti confirming whether it would stick with Honda engines for 2018 was understood to have led Sato, who has close ties with the manufacturer, searching for an alternative berth.
He joins Graham Rahal, who scored a pair of wins at Detroit this year en route to sixth-place in the championship, in an expanded two-car RLL line-up, which also marks his return to the team he previously drove for in 2012.
"I'm excited about having Taku back with us," said team co-owner Bobby Rahal.
"I have such admiration for his spirit and how he approaches everything and was so happy for him when he won the Indy 500 this year.
"The chance to bring him back to the team was too good to pass up.
"He and Graham get along very well and we will have two strong cars that can win any race in 2018.
"I think that will give our team a great chance at being contenders in every race but it's also going to give each of our drivers a chance to have their best years ever.
"I'm excited about it and even though the 2017 season just concluded, I can't wait for the 2018 season to start."
Sato added: "I am extremely happy to be back with Rahal Letterman Lanigan Racing. Bobby, Dave [Letterman] and Mike [Lanigan] have always been very supportive of me.
"The team has been ultra-competitive the past few seasons. I can't wait to be a part of it in 2018."
Rahal Letterman Lanigan ran a single car for the majority of the 2017 campaign for Graham Rahal, although it fielded a second entry for Oriol Servia at Indianpolis and Detroit and for rookie Zachary Claman DeMelo at the Sonoma finale last weekend.
It last ran two cars for a full season in 2013, when James Jakes partnered Rahal.