Tommy Haas has received U.S. citizenship but will continue to play for Germany.
Writing on his website, Haas said he has completed the naturalization process by sitting the U.S. citizenship test in December and taking the oath of allegiance on the 27th of January.
"In Tampa, along with about 300 other immigrants from over 70 different countries, I raised my right hand to swear the oath of allegiance," said Haas. "I desperately wanted to do this because the United States have really become my home over the past years and that's why I considered it a logical step to apply for naturalization."
Haas has been based largely in the United States since attending the Bollettieri academy as a teenager. He is engaged to American actress Sara Foster.
But the 31-year-old said he plans to keep representing Germany in international competition. "Of course I wouldn't have done this if I hadn't had the option to keep my German passport. But as this point was guaranteed, I now have the privilege of dual nationality and I can continue playing for the German Davis Cup Team."