EastEnders gets new "force of nature"
Best will play Dexter, the 20-year-old son of new character Ava Hartman.
Ava is the long-lost daughter of Cora Cross and makes her debut in EastEnders on November 20.
Dexter arrives in Albert Square in January 2013.
EastEnders' Executive Producer Lorraine Newman said: "Dexter is a force of nature: cheeky, forthright, confident but highly protective of his mum and vice versa. He'll work at the Arches and be a great mate for Jay and Lola. I am sure he'll be hugely popular with the audience."
Best said of his casting:
"Working with such great actors so early in my career is an amazing opportunity. I am really excited to see what the writers have in store."