In a statement, his family said the star had passed away following the long-term battle with a progressive lung condition, idiopathic pulmonary fibrosis, which rapidly worsened towards the end of this year.
They said: “Keith died peacefully at home shortly after midnight on the 11th of December. His wife Maria, his daughter Rose and his son Ted were by his side.
“Keith was a loving husband, father, son, brother, uncle and friend. We would respectfully ask to be left to mourn his passing in private.”
Among the first to pay their respects was his ex-wife, Maggie Philbin, who Keith met and fell in love with when the pair co-hosted ‘Multi-Coloured Swap Shop’ in the 1970s.
In a statement on her official website, the TV presenter said he was a “one off”, and recalled seeing him just a matter of weeks ago.
“I saw him two months ago at his sister Janice’s wedding, where he was still attempting to be life and soul of the party despite being on portable oxygen and made sure he knew how much he meant to us all,” she wrote.
She added: “Keith was loved by everyone who knew and worked with him. He leaves us all with very special memories.”
Some of the most well known names from the world of showbiz also paid tribute on Twitter...