LONDON, Feb 2 (Reuters) - Austrian Christian Klien will be BMW Sauber's test and reserve driver this season, the Formula One team said on Saturday.

"We wanted a third driver with Formula One racing experience," said team boss Mario Theissen in a statement. Klien, 24, competed for Jaguar and Red Bull in 2004 to 2006 before spending a year testing for Honda.

Estonian Marko Asmer, 23, will be the team's second test driver.

"With Christian we have signed on a driver who is familiar with the format of a grand prix weekend and can step into the breach right away should one of our team drivers have to back out," said Theissen.

BMW Sauber, overall runners-up in 2007 after McLaren were stripped of all their points for a spying controversy, needed to use German Sebastian Vettel as a stand-in at last year's U.S. Grand Prix after Poland's Robert Kubica crashed heavily in Canada.

Vettel subsequently moved to Toro Rosso as a full race driver while Germany's Timo Glock, who took over as BMW's reserve in 2007, will be competing for Toyota when the season starts in Australia on March 16.

Klien had hoped for a race seat with Force India this year but lost out to Italian Giancarlo Fisichella.