"We thank you for all your messages and support and promise to end the show on an incredible high."
The actor was best known for her roles as Peggy Mitchell’s sister Aunt Sal in the BBC soap and as Olive in the 1970s sitcom.
"Since appearing in the very first episode of EastEnders, Leonard created a truly iconic character in Dr Legg, who will always be remembered."
The actor is leaving his role as Queen Vic landlord Mick Carter after more than eight years.
The actor has played Mick Carter since 2013, but is moving onto pastures new later this year.
"Everyone thinks I am Ian Beale and so it’s going to be great to show I am not."
Her character also has a connection to former cast member Jason Donovan.
The Coronation Street icon is one of two stars confirmed for the new line-up.
ITV has confirmed that Norris is set to die in an upcoming storyline.
We know him best as Corrie's David Platt, but Jack came close to a leading role in a huge British film.