David Coulthard tested a Mercedes DTM car at Alcazaba in southern Spain this week.
The 38-year-old Scot retired from Formula 1 at the end of the 2008 season but has made no secret of his interest in racing elsewhere in the future, although no deal has yet been made with Mercedes.
Former grand prix winners Mika Hakkinen, Jean Alesi and Heinz-Harald Frentzen raced in the DTM after their F1 careers were over, while Ralf Schumacher is currently driving for Mercedes in the series. Kimi Raikkonen and Valentino Rossi have also tested DTM machinery, and the series has stated that Coulthard's test "does not allow direct conclusions about a possible commitment for the 2010 season."