The veteran actor passed away at a hospital in Texas after suffering complications from his battle with cancer, during which he continued to shoot scenes for the revamped Dallas TV show.
He is best remembered for his portrayal of scheming oil baron J.R. Ewing in the original version of the soap opera, which ran from 1978 to 1991, and many of his famous fans have taken to Twitter.com to express their sadness at his death.
Actress Matlin, writes, "RIP Larry Hagman. His portrayal of JR Ewing on Dallas was iconic but I loved him as well in I Dream Of Jeannie. RIP, " while Vanessa Williams posted a picture of herself posing with Hagman, with the caption, "RIP to the amazingly charming Larry Hagman."
Veteran TV host King admits he was stunned by news of the star's death, and praised the actor for helping him out over the years: "I'm shocked. Larry Hagman was a dear man who had an incredible career. He helped me to stop smoking. He really was a very special person."
TV's self-styled "Mr. Nasty" Cowell honoured Hagman as the "best baddie" on the small screen, writing, "Very sad to hear about larry hagman. He was the best TV baddie and from people who met him all said he was a great guy. He will be missed."
Star Trek actor William Shatner, adds, "My thoughts and prayers go out to the family of Larry Hagman," and TV star Sharon Osbourne writes, "So sad to hear about the passing of Larry Hagman. Sending love and respect to his family. "
British star Martin Kemp recalls Hagman's most famous Dallas storyline: "RIP Larry Hagman... I was part of the 'Who shot JR' generation. Hat tipped to you," while Irish singer Ronan Keating honoured Hagman as an integral part of his childhood, adding, "Fond memories of watching Dallas with my mam (mother). Goodnight Larry and thank you. Legend."