Former Blue Peter presenter John Noakes, who hosted the show in the 1960s and 1970s, has died aged 83.
Noakes was the BBC children's show's longest-serving presenter, appearing for more than 12 years, and was often seen with his dog Shep by his side.
He was also known for his daredevil stunts like climbing Nelson's Column and jumping out of planes - and for his famous encounter with a baby elephant.
A family statement said he had "endured and suffered from" Alzheimer's disease.
"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," it said.
"His many escapades with his faithful companion Shep, during his time with Blue Peter, will live on in many peoples memories. That is how his family would like him remembered."
Noakes joined the show at the end of 1965 after training as an engine fitter for the RAF, and stayed until 1978.
He became a favourite as the show's action man, and continued to play on that image with several series of Go With Noakes, where he travelled around the UK with Shep alongside him.
That led to his catchphrase "Get down Shep!" - which even became the title of a song by comedy group The Barron Knights.
Noakes appeared on Blue Peter with co-presenters including Christopher Trace, Valerie Singleton, Lesley Judd and Peter Purves.
Purves told BBC News that Noakes's death was "very sad" but added that the Alzheimer's had become "extremely serious" in recent years.
Remembering his friend, he said: "He was unique. He had qualities that no-one else had and he'll be remembered very fondly by a lot of people, and none more so than me."
He was "very, very brave" in doing his many stunts and adventures, Purves added.
"We had so much fun together over the years. There were hundreds and hundreds of happy memories. I'll never forget him."
John Noakes's most memorable TV moments
THAT elephant: Noakes revelled in the merry chaos that erupted when a frightened baby elephant called Lulu misbehaved in the studio. He cried "ooh, get off me foot!" as he tried to get hold of Lulu - and the rest is British TV history.
Bobsleigh bruises: When he shot down the Cresta Run in Switzerland, the camera travelling with him, viewers saw him crash out at high speed. They also saw him lower his trousers to show the bruises on his thigh afterwards.
Flying high: With the help of the RAF, Noakes jumped out of a plane in 1973 to became the first civilian in Europe to freefall from a height of five miles.
Nelson's Column: In a task that would never pass a modern risk assessment, Noakes scaled a series of ladders to reach the top of Nelson's Column in 1977, telling viewers he was "literally hanging from ladder with nothing at all beneath me".
Shep's death: Nine years after he left Blue Peter, an emotional Noakes returned to the BBC on a programme called Fax, presented by Bill Oddie, to break some "very bad news". Fighting back tears, he informed the nation that Shep had died.
Other previous Blue Peter hosts added their tributes.
Janet Ellis, a presenter from the 1980s, wrote: "The best, bravest, funniest BP presenter. If we didn't walk in John Noakes' shadow it's because he shone the light for us. RIP".
Sarah Greene added: "Deepest condolences to the family of John Noakes. He made us feel we could all get out there & whizz down the Cresta Run, he broke the bounds."
Zoe Salmon, who fronted the show between 2004 and 2008, tweeted: "I am deeply saddened to hear about John Noakes, a Blue Peter legend who will live on in our hearts. Privileged to have met him."
Katy Hill wrote: "SADDEST news about the legendary John Noakes who inspired me to want to present Blue Peter & do EVERYTHING he did. THE BEST!"
BBC director general Tony Hall described Noakes as "one of the BBC's most loved children's presenters".
In a statement, he said: "He was a warm and engaging presenter who appealed to all ages and provided children's TV with some of its most memorable moments. He will be missed by his many friends and family."