Adderly Fong has joined the Lotus Formula 1 team's roster of development drivers for 2015.
The 25-year-old from Hong Kong had a relationship with Sauber last season that included a Friday practice outing at the Abu Dhabi Grand Prix.
Lotus said his deal would involve "a driver development programme as well as contributing to the team's simulator work", alongside his already-announced GP3 campaign with Koiranen and a GT Asia season.
"This is a great opportunity to further my racing career; I'll be able to learn how an F1 team operates during race weekends as an integral part of the team and these invaluable experiences are going to lay the foundations of my future development as an F1 driver," said Fong, who had a mixed GP3 and sportscar programme in 2014.
Fong joins Carmen Jorda as a Lotus development driver, while GP2 champion Jolyon Palmer is the team's official reserve.
Lotus CEO Matthew Carter added: "We have an aggressive development programme with the E23 so [Fong] will be able to both learn from our engineers and race drivers as well as contribute to our car through the course of the season.
"We have a very strong driver line-up which Adderly will join so he has a great opportunity to learn ahead of him.
"We are committed to moving back up the competitive order and Adderly's work behind the scenes will be invaluable in assisting us to achieve this."
F1 TEST/RESERVE/DEVELOPMENT DRIVERS 2015
Sebastien Buemi, Antonio Felix da Costa
Susie Wolff, Alex Lynn
Esteban Gutierrez, Jean-Eric Vergne
Kevin Magnussen, Stoffel Vandoorne, Oliver Turvey
Jolyon Palmer, Carmen Jorda, Adderly Fong
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