The 37-year-old actress was cast in the role of Tina earlier this year and makes her first appearance on the BBC One soap next week.
Tina is the sister of established regular Shirley (Linda Henry). Viewers will see that Shirley has been staying with her estranged sibling during her time away from Albert Square.
Bradshaw-White told TV Times: "I'd never wanted to do EastEnders. I always thought, 'God no, I can't cope with that sort of fame'. But all of a sudden I got older and felt more chilled out.
"The casting director said she had me in as her wild card for Shirley's sister. The character was originally supposed to be an overweight 50-year-old who's past it. I turned up looking lovely to ask them if they had anything else, and they rewrote it for me."
She added: "It's such a good part. Tina is really funny and has some brilliant one-liners. She and Shirley spend a lot of time shouting, but there's real love there. They don't shout through anger, it's just what they do, and the next minute they're talking normally or giggling."
Shirley and Tina's brother Mick, played by Danny Dyer, will also be joining the Square with his family at Christmas.
Bradshaw-White's previous screen credits include roles in This Life and Holby City.
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