The former Juventus striker signed for the Baggies last week.
â€œNicolas seems a really lovely lad," Foster told the Albion website.
â€œAfter the first session you could see little glimpses of what he has got. Heâ€™s going to be a fantastic addition to the squad. Iâ€™m sure everyone will welcome him.
â€œWeâ€™re all looking forward to seeing him in action. I really want to see his butterfly celebration too.
â€œI always remember seeing him do that when he scored goals at Chelsea. Itâ€™s an awesome celebration.
â€œI want to see him do it plenty of times this season!"