EastEnders favourite Dame Barbara Windsor, 78, is leaving the show for good and her famous character, Peggy Mitchell, will be killed off.
On Friday night's episode Peggy returned to Albert Square and told her son Phil (played by Steve McFadden) that her cancer had returned.
But unlike her previous storyline on breast cancer she will not win her battle against the disease and will die.
Dame Barbara said despite her decision to leave the soap, her love for the show would never change.
Mr Treadwell-Collins said: "Barbara is the real guvnor of EastEnders. "So when she told me her decision back in the summer, we both had a little cry before getting excited about how Peggy Mitchell, the matriarch to end all matriarchs, could bid her final farewell to Albert Square."
He praised Windsor for creating one of the "greatest ever characters on British television" and said her exit would be "one of the most heartbreaking, uplifting and epic exits an EastEnders character has ever had."