The 42-year-old comedian will play a '21st century villain with a twist' and will shake up the 30th anniversary week.
Dominic Treadwell-Collins revealed: "Richard has always been on our EastEnders wish list – and now the perfect part has come along.
"He's an authentic London and a terrific actor, bringing with him warmth, humour and energy which will add so many laters to this 21st century EastEnders villain.
"The status quo in the Square is about to be well and truly shaken up."
Speaking to the Sunday People about his new role, Richard said: "EastEnders is a show I've grown up watching so to film on Albert Square is something I'll never get used to.
"To know my ever scene will be a live one hopefully means the team believe in me and I won't let them down."
To celebrate 30 years, EastEnders will have a week of live episodes during which the identity of Lucy Beale's killer will be revealed.
Speaking previously, Dominic said: "This is a fantastic opportunity for EastEnders to create a massive national event and one that will enable us to celebrate 30 years in spectacular style.
"With live elements to each episode as well as a half hour live episode, it allows us to have a huge element of surprises for the audience."