The 18-year-old, who was born in Florida to a German mother and American father, has represented both Germany and the United States at youth level, but has now pledged his allegiance to Jurgen Klinsmann's side and a potential place at the World Cup in Brazil.

"It's super! He is a great talent with a brilliant future ahead of him," said a delighted Klinsmann, who coached Germany at the 2006 World Cup and is a former international striker for the Mannschaft.

Green has already been included in the US squad for a World Cup preparation match against Mexico on April 2 in Glendale, California, but admitted his decision to play for the Americans was not taken lightly.

"It was a difficult decision, taken after a long discussion with my family," said Green who has come up through the Bayern youth system to make his first-team debut last November in a Champions League tie against CSKA Moscow.

"It would be crazy (to play at the World Cup), but to get there, I have to work extremely hard." said Green.