The actor’s closest co-stars, Linda Gray and Patrick Duffy, who played wife Sue Ellen and brother Bobby, were at his bedside in a Dallas hospital.
Linda’s agent Jeffrey Lane said: “Linda was with him.
“They had been friends for 35 years and they had worked together for many years so obviously it is devastating.
“She called and told me. She sounded very sad.”Larry was in the middle of filming the Dallas comeback series.
A spokesman for Hagman said the family were “devastated”.
Larry had a lifesaving liver transplant in August 1995 and had battled cancer. But he had been optimistic about the future and told how he was fighting the condition by becoming a vegan.
The dramatic moment when his Dallas character was gunned down in his office in 1980 inspired the legendary phrase “Who shot JR?”.
Sue Ellen’s sister Kristin Shepard — played by Mary Crosby — was unmasked as the killer in an episode watched by 350million viewers worldwide.
Linda said last night: “Larry Hagman was my best friend for 35 years.
“He was the Pied Piper of life and brought joy to everyone who knew him. He was creative, generous, funny, loving and talented. I’ll miss him enormously.”
Larry was born in Fort Worth, Texas, in 1931. His mother Mary Martin was a star of Broadway. He married Swedish-born Maj Axelsson in 1954 and the couple had two children — Heidi Kristina and Preston.
Larry openly admitted to alcohol problems during his life and would often drink champagne on set.
His relationship with the bottle led to his 1995 liver transplant. His wife was diagnosed with Alzheimer’s in 2008.
I was a huge fan of the show and watched the Dallas reboot on TNT. He still had it. Very sad to see, but what a life this TV Giant had. Let me know what you think on my facebook page by clicking here.