Former 'Grange Hill' actress Lisa Hammond will play tough market trader Donna Yates, who declares war on stall holders Bianca Butcher (Patsy Palmer) and Kat Moon (Jessie Wallace), and the 31-year-old star is looking forward to playing a "bad" character.
She said: "I'm really excited to join 'EastEnders'. Donna is a bit of a handful but they are always the most fun characters - it feels good to be bad."
Donna wasn't originally written as a wheelchair-bound character, but Lisa - who has a restricted growth condition - won over producers with her audition, and show boss Dominic Treadwell-Collins is delighted to have her on board as the "flinty, aggressive and difficult" stall holder.
He added: "Donna's not an easy character to like at first. As we get to know her better, we will discover a funny, loyal but also fragile woman underneath.
"Lisa is a brilliantly comic and sharp actress. We have been trying to get her into the 'EastEnders' cast for a long time so I am delighted."
Donna is the second regular disabled character to appear on Albert Square, following Adam Best (David Proud), who appeared from 2009 to 2010.
Lisa began her career at the age of 13 and has also starred in 'Pyschoville', 'Bleak House' and 'Max and Paddy's Road to Nowhere'.