The 23-year-old will sign a four-and-a-half-year contract at Wigan and could cost the club anywhere up to £7million.
“I found out eight or nine days ago,” Ruben told the club’s official website.
“Since then the club have continued with negotiations with my agent and he told me it was done and all that was needed was my signature.
“I am happy to take this opportunity because it is a good coach (Roberto Martinez) and a great team.”
