Sauber Formula 1 driver Marcus Ericsson will switch to IndyCar in 2019, driving for Schmidt Peterson Motorsports as full-time team-mate to James Hinchcliffe.
Ericsson has raced with Sauber for the past four seasons, and will have made 97 F1 starts when he competes in the season-closing Abu Dhabi Grand Prix next month.
Sauber is making a complete line-up change for 2019, with 2007 F1 champion Kimi Raikkonen joined by Antonio Giovinazzi as Charles Leclerc moves to Ferrari and Ericsson is demoted to a reserve role.
The 28-year-old Swede quickly made clear that he wanted to combine that F1 link with a full season racing elsewhere and will now join the IndyCar grid.
"It's a great honour to be picked as one of the drivers at Schmidt Peterson Motorsports and IndyCar for the 2019 season," said Ericsson.
"It feels like a perfect step for me and my career after five years in F1.
"I can't wait to start work with SPM and all the people in the team which I've heard a lot of good things about.
"They've had some great success over the years, and I'm looking forward to working hard to continue and improve on that path.
"The racing in IndyCar looks great and I feel really excited to be part of it in the future.
"It will be a lot to learn including new tracks, oval racing, etc.
"I know it won't be easy, but it's a challenge I'm very much looking forward to and I can't wait to get started."
SPM fielded Hinchcliffe and Robert Wickens as its full-time 2018 line-up until Wickens was seriously injured in a horrific crash at Pocono.
Ericsson will race the #7 SPM Dallara-Honda because team owners Sam Schmidt and Ric Peterson have pledged to keep the #6 entry reserved for Wickens "when he wants to and is able to return".
Schmidt said he and Peterson were "excited to welcome Marcus" to IndyCar.
"He has a tonne of experience racing in the top levels of motorsports, so we believe that he will be able to contribute to our development programme that began in earnest in 2018," Schmidt added.
"While the circuits on the IndyCar schedule will be brand new to him, particularly the ovals, we have a lot of confidence and trust in his eagerness to learn along with his work ethic.
"We think he and James will be a good fit to push one another and fight for those wins."
Jack Harvey will also retain a link with the team through SPM's collaboration with Meyer Shank Racing - which aims to continue an expanded but still part-time schedule.
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