West Brom have been trying to sing the South American for much of the summer.
“Gonzalo is an exciting, quick, technical and aggressive player,” Baggies boss Roberto Di Matteo told the club’s official website.
“He’s a Chile international and very versatile, which will give me good options.
“He’s still young (at 24) and has a strong desire to achieve.
“Gonzalo wants to go to that next level and prove himself in Europe.”
