Alice, who is Derek's long-lost daughter, makes her first appearance on Albert Square this evening (May 10) after deciding to track down her dad.
Show bosses recently promised that Alice's arrival will allow fans to see Derek's softer side as he fights to win her approval.
Banks told All About Soap of the storyline: "He really wants a relationship with Alice, which is lovely. She thinks he's a nice guy who cares about his family.
"She makes him work to be part of her life, though. He has a lot to do to prove himself."
Discussing the other Brannings, the actress said: "She has no idea they even exist! They're an added bonus. It's a lot to take in - she gets to Walford and suddenly discovers there's this huge family she's a part of."
Banks explained that she was "thrilled" when she heard that EastEnders bosses had chosen her to play Alice.
"I was working in a bar when they called to say I got the part," she commented. "I've always been a fan of the show and I'm pleased to be joining such a great family."
EastEnders continues tonight at 7.30pm on BBC One.