The TV star, who plays Zainab Masood, has also appeared in BBC's Goodness Gracious Me and will declare the annual festivities open at 12pm on Saturday, June 30.
Paul Kardos-Stowe, chairman of the carnival committee said: "It is very exciting to have someone as well-loved as Nina to come and open the event and we are very grateful to her for giving up her time to support us.
"We are sure that many people will want to come along and see her and it will get Carnival Capers off to a great start."
As well as having the chance to get Ms Wadia's autograph, visitors can enjoy a circus skills area, fun fair, dog show and more.
Local businesses and organisations will also hold stalls at the carnival, which is sponsored by Wentworth Removals.Schools churches and dance groups will put on performances in the main arena.
Carnival Capers will be on Cabrera Green Playing Fields in Cabrera Avenue on Saturday, June 30, from noon-5pm.