The Big Yin was born on the floor of a room and kitchen in Anderston, Glasgow, on November 24 1942, weighing 11lbs and 4 ozs.
After leaving school, the comedian, actor, musician, playwright and presenter began working in John Smith’s bookshop and Bilslands Bread before becoming a welder in the Glasgow shipyards.
He started his showbiz career with Gerry Rafferty and the Humblebums, performing his first solo stand-up show in Paisley in 1965.
Since then he has grown into a house-hold name and his affectionate anecdotes about life and his upbringing in Glasgow have ensured that he is regarded by many as one of the best alternative stand-up comics in the world.
A star of stage and screen, he has presented shows including the Billy Connolly’s World Tour series and A Scot in the Arctic and made guest appearances in The Roseanne Show, 3rd Rock from the Sun, Super Gran and Worzel Gummidge. He has also appeared on Parkinson nine times.
Following the success of his comedy career, he turned his hand to acting, appearing in films including The Return of the Musketeers, Brave, Mrs Brown, with Dame Judi Dench, and Muppet Treasure Island.
His worldwide success is a far cry from his upbringing in Glasgow where, as a child, he was abandoned by his mother, molested by his father, routinely beaten by his aunts and belted by his teachers.
He also battled with alcohol and stopped drinking on December 30 1985.
After his first marriage fell apart, the life-long Celtic fan met comedienne turned psychologist, Pamela Stephenson, in 1979 and they married in 1990. He has three daughters, Daisy, Amy and Scarlett, with Pamela and a son, James, and daughter, Cara, from his first marriage.
The comic’s life has also been the subject of two books written by his wife called Billy and Bravemouth.
Billy is now set to star in Dustin Hoffman’s directorial film debut, Quartet, with Maggie Smith and Michael Gambon, before appearing as dwarf warrior Dain Ironfoot in The Hobbit next month.
Speaking to the Herald earlier this year about his up-coming birthday, the Big Yin said: "I feel lovely. I feel as if I'm 37. I've never really given much credence to the age thing. I don't have a bus pass and I don't intend getting one. I don't feel old. I think the trick is not to grow up. It's growing up that causes the problem – people do that growing-up stuff and start thinking in beige."