The 24-year-old Morocco international has joined on a season-long loan from Championship side QPR.
Hangeland told BBC London 94.9: "I'm very excited to have him on board and it was a welcome surprise for us.
"It will be down to him to prove he can be consistent and work hard. His talent is unquestionable."
He added: "He caused us a lot of problems playing for QPR last season so I am happy he is on our team now."