Barrios, who joined from Colo Colo for €4.5million, hit an astounding 37 goals in 38 games for the Chilean champions last term.

Dortmund said in their official site that the 24-year-old grabbed attention in training by scoring three goals in a practice match.

"We´ve been interested in him for quite a while. We approached him very early and have observed him for a very long time - and not only watched his 37 goals on YouTube," said Dortmund boss Jurgen Klopp.

"He´s strong, has a physical presence with his height of 1,89m [6ft. 2] , is aggressive, has a great shooting technique. We now have another option up front where we are already well covered."

Dortmund's frontline already boasts the likes of Egypt striker Mohamed Zidan, Paraguay's Nelson Valdez and Bulgarian Dimitar Rangelov.

Watch Barrios' goals in Chile