The former Ajax striker has already made an impact since arriving on transfer deadline day.
"He is going to be very good for us. I'm sure of that. I phoned Luis just before the deal was completed and told him he was signing for a big club," said Kuyt.
"He is adapting to things very quickly. He had to sort out a lot of things in his first week but every day in training he has been totally focused. He wants to be an important player for this club. He has shown already that he will be."