The pair have been involved in the development of Polestar’s new TC1-spec S60, along with Robert Dahlgren, who will continue with WTCC test duties while returning to the Scandinavian Touring Car Championship.
Bjork won the last three STCC titles with Polestar, where he and sometime CART Indycar driver Ekblom were team-mates in the works Volvo squad.
Team CEO Christian Dahl said: “Thed and Fredrik are two of the very best touring car drivers in the world and they have achieved remarkable results for us in the past.
“Both of them have played a vital part in the development of our new race car and I am keen to see them start our journey towards the top of the FIA World Touring Car Championship.”
Bjork described his first full season of international racing since his sportscar days in the early 2000s as a “dream come true”.
The 35-year-old added: “This is the most excited and motivated I have been for a season in my entire career.
“I have no doubt we have what it takes to work our way to the top fight and the season start cannot come soon enough.”
Ekblom, whose CV also boasts three titles in the STCC’s Swedish predecessor, said he accepted that catching the likes of dominant WTCC champion team Citroen would be tough but was ready for the challenge.
“To race in the WTCC has been my goal ever since joining Polestar Cyan Racing in 2012 and I am proud to represent the team in a world championship,” said the 45-year-old, who contested three WTCC rounds in an RBM-run BMW in 2007.
“We have an amazing journey ahead of us and I will put everything to it.
“While we have a lot of development work ahead of us to catch up with the frontrunners, we will be pushing hard from the first race.