Valdez, whose initial contract was due to end in June 2010, is now tied with the Black Yellows until the summer of 2012.

"We held talks with Nelson for a while and now we have completed them," Dortmund sporting director Michael Zorc told the club's official site.

The 25-year-old forward has been enjoying life at Signal Iduna Park since joining from Werder Bremen in 2006.

Valdez, who scored four league goals so far this term, usually partners Alexander Frei upfront in Jurgen Klopp's roster.