Real name Geoffrey Rowe, the comedy star died on December 14 2021 at the age of 73 after contracting Covid-19.
A service was held for the comic in the packed Truro Cathedral on Monday from midday, after a motorcade in his honour.
Cars had driven from his club in Lewdown, Okehampton, visiting Lifton, before arriving in the town where a procession was held at the war memorial.
People lined the streets and queued to get into the cathedral as the procession arrived.
Jethro’s wicker coffin had been transported in a black Toyota 4×4 with a number plate reading J35TER, resting on a Cornish tartan blanket.
He was then carried into the church by six pallbearers to the song Welcome To My World, by Jim Reeves.
Reverend Canon Alan Bashforth and Reverend Tim Hodge who led the service called Jethro “one of Cornwall’s most significant people of recent times”.
Rev Hodge then spoke of Jethro’s life, describing him as a “well-loved and cantankerous character”.
His long-time manager and friend John Miles MBE detailed Jethro’s rise to stardom, but said: “Fame never changed Jethro.”
Mr Miles’s anecdotes included Jethro having to clean up his explicit act to perform for the Queen and her friends at Ascot Racecourse and that the Prince of Wales, who he met and performed for on a number of occasions, joked that the comedian owned more land in Cornwall than him.
Mr Miles added: “There will never ever be another Jethro.
“You gave us so much enjoyment Jethro, bless you. Rest in Peace.”
Hymns including The Old Rugged Cross and the traditional song Trelawny were sung, accompanied by Cornish folk band The Oggymen.
And a poem called, Ever Since I Heard The News, written by Paul Jackson in tribute to Jethro from the point of view of his fans, was read out and included the words: “Oh I laughed each time I saw you, so much I almost cried.
“Tears fell once again this week, when I heard that you had died.
“The cream of British comedy, lesser mortals were in awe.
“And every time I saw you, I simply wanted more.”
It was followed by an eulogy by well-known stand-up comedian Jim Davidson who induced burst of laughter from the attendees by regaling them with tales about Jethro’s performances and how he viewed the world.
But Mr Davidson also spoke emotionally of a hope that he would one day see his friend again, and said: “I look at it this way, my old boy, what a caterpillar calls death a wise man calls a butterfly, so you go fly Geoff.”
Jethro was then carried from the cathedral to tune of his own rendition of Red Rocks And White Waters, written by Franc Yonco.
A private burial was to be held for immediate family members only including his life partner Jennie, sons Jesse and Lanyon, stepdaughter Sarah, daughter-in-law Stacey and his grandchildren.
During the service a brown leather bag was placed on his coffin, which was said to have gone with him for every appearance he made, but its contents have been and will remain a secret.
Over 5,000 people tuned in to watch the service which was broadcast virtually on YouTube by his friend and driver Andy Reed.
Born in St Buryan, the youngest of four children, he first worked as a carpenter’s apprentice and then for a time down one of the mines that were still working in Cornwall at that time.
He loved rugby, playing for the Penzance Pirates, and clay pigeon shooting, winning the English Open in 1990, but his main passion was performing.
Jethro built his name as a comedian in the 1980s and 1990s with his brand of observational comedy, rocketing to fame after making his first national television appearance on the Des O’Connor Show.
In 2001, he performed in the Royal Variety Show and went on to become one of the biggest stars from Cornwall selling over four million DVDs.
He only announced his retirement in 2020 after almost 50 years of touring.
He was due to perform his last tour dates but they were later postponed due to the onset of the coronavirus pandemic.
Donations in memory of Jethro were asked to be made to the Children’s Hospice South West.