She became a household name playing chief yellowcoat Gladys Pugh in BBC One's hugely successful TV series about a holiday camp set in the late Fifties, but her career also spanned an array of roles in theatre and musicals, from Fiddler On The Roof to Gypsy.
Her agent said she died on Friday while in hospital following surgery for a fall she had earlier in the week, which had led her to withdrawing from performing in Aladdin at the Princess Theatre in Torquay.
They hailed her as a “real legend of the British entertainment scene.”
A statement said: "It is with much sadness that we have to announce the death of our dear and much-loved client Ruth Madoc.
“From film work such as Fiddler On The Roof and Under Milk Wood with Richard Burton and her iconic TV performance as Gladys Pugh in Hi De Hi! and more recently in Little Britain and on stage with Calendar Girls - the play and the musical - plus recent acclaim in short films Skinny Fat and Cardiff, she was truly a national treasure and was looking forward to getting back on the road in 2023 with The Best Exotic Marigold Hotel.
"A real legend of the British entertainment scene she was one of a kind and a unique talent loved by many. She is gone far too soon. Our hearts are broken!
Her death came following a fall which led her to withdraw from performing Aladdin at the Princess Theatre in Torquay.
Born in April 1943 and brought up in Llansamlet near Swansea, Madoc trained at the Royal Academy of Dramatic Art (RADA) before her break-out role playing Fruma Sarah in the film version of the musical Fiddler On The Roof in 1971.
A decade later she appeared in Hi-de-Hi!, having had other roles including Mrs Dai Bread Two in 1972 comedy film Under Milk Wood.
In 2018, Madoc overcame her fears to reveal her breasts to a live audience in the ladies' version of The Real Full Monty alongside Coleen Nolan.
She is survived by her two children.