Former Blue Peter host John Noakes has died aged 83, a family friend has announced.
His family said he died peacefully in his sleep on Sunday morning and that they hoped Noakes would be remembered for "his many escapades with his faithful companion Shep" during his time on the TV show.
He had been suffering from Alzheimer's.
Family friend Wendy Downes said in a statement: "John Noakes died peacefully on Sunday morning, May 28.
"He had endured and suffered from Alzheimer's over recent years and whilst he will be greatly missed by his wife, family and many friends, his release from continuing ill health must be counted as a blessing.
"His many escapades with his faithful companion Shep, during his time with Blue Peter, will live on in many peoples memories and that is how his family would like him remembered."
Blue Peter's Action Man
During his long tenure on Blue Peter, John Noakes developed a reputation as the show's action man.
His feats included ascending Nelson's Column without a safety harness using just a rickety wooden ladder - a sound problem meant he had to repeat the climb - a bruising encounter with a bobsleigh and a record-breaking skydive.
The Yorkshire-born star was Blue Peter's longest-serving presenter, making his debut on the BBC's children's show in 1965 and staying until 1978.
Noakes initially found the TV cameras terrifying and said that he felt as though he had been "stripped naked".
"I actually shook with fear... I went through murder. I even went to a hypnotist and a faith healer to try to get me out of it," he said.
He told how he only survived the job by acting the clown and developing an on-screen persona as "this idiot called John Noakes".
As well as being the show's daredevil, Noakes was also known for his partnership with canine stars of the programme, Patch - the first Blue Peter dog Petra's puppy - and the border collie Shep, who inspired Noakes's catchphrase: "Get down, Shep!"
The phrase later inspired the name of a pop song released by Barron Knights.
Born in Shelf, near Bradford, Noakes began his early adult life training as an engine fitter for the RAF before deciding to become an actor and studying at the Guildhall School of Music and Drama.
He notched up small TV parts in series like Redcap and Mogul and landed the Blue Peter job after editor Biddy Baxter decided to have a third presenter on the show to join Christopher Trace and Valerie Singleton.
She spotted a picture of Noakes in an article about a local theatre production of Hobson's Choice in the pages of the Leicester Mercury after returning to her home city for the weekend.
The flagship children's show made Noakes a household name.
Trace was later replaced by Peter Purves and the trio of Singleton, adventurer Noakes and Purves became a classic line-up.
One of Noakes's most memorable moments on the show was when he was asked to drop his trousers to show his bobsleigh-induced injuries - he realised he was wearing his wife Vicky's underwear which he had put on by accident in the dark.
As well as Blue Peter, Noakes made 1970s travelogue spin-off Go With Noakes, where he travelled around the UK with Shep alongside him.
When Noakes left Blue Peter, the BBC had let the presenter keep Shep but he was forbidden from using the dog in adverts.
He wrote a children's book, The Flight Of The Magic Clog, and appeared on reality shows I'm Famous And Frightened and Britain's Worst Celebrity Driver Live.
In 1982, he left England on a sailing trip to see the world but, he and his wife were shipwrecked in a hurricane.
In 1984, they set out again two years later and settled in Majorca.
Noakes said later that he had not been happy on Blue Peter and that he was not paid what he was promised.
"When I left I was offered the part of Willy Mossop in Hobson's Choice at Oxford and three weeks of doing that gave me the equivalent satisfaction to 12 years of TV," he said.
He also hit out at the show's editor, saying: "Biddy Baxter was an awful woman. I don't want to talk about her."
But fans of the show would see him reunite with his former co-presenters for Blue Peter anniversary celebrations, including the time capsule dig in 2000.