McLaren announced the appointment Friday and said Kovalainen would begin practicing with the team in January. Kovalainen joins Lewis Hamilton of Britain, who finished second in the 2007 drivers' standings behind another Finn - Ferrari's Kimi Raikkonen.
McLaren chief operating officer Martin Whitmarsh said the team looked at other drivers, but opted for Kovalainen because he and Hamilton would provide the most competitive lineup. This past season, Alonso and Hamilton feuded often and the Spanish driver quit McLaren and recently moved to Renault.
The British-based McLaren is hoping the coming season will be less turbulent that 2007, where it was fined $100 million and stripped of its points in the constructors' standings for unauthorized possession of secret Ferrari documents.
Kovalainen is the third Finnish driver to compete for McLaren after Mika Hakkinen and Raikkonen. Hakkinen won two world driving titles with McLaren - in 1998 and 1999, the last time the British team captured the drivers' championship.
Some information for this report was provided by AP.