The actor played scheming oil baron J.R. Ewing in the legendary programme, which chronicled the glamorous life of a wealthy Texan family and the corrupt double-dealing of its business empire.
The show became a massive hit around the world, attracting global audiences of more than 100 million before ending its 13-year run in 1991.
During its peak in the mid-1980s, Romanian President Ceausescu agreed to allow the show to be broadcast in the then-Communist country in a bid to show his citizens the decadence of democratic nations - but Hagman is convinced the plan backfired and led to a revolution and Ceausescu's eventual execution.
He tells Australian newspaper the Fairfield City Champion, "Romania put on Dallas to try and show how corrupt the American system was and it ended up with them lining up Ceausescu, who was the dictator, and shooting him 500 times - they wanted all that stuff they didn't even know was out there.
"He let that show in to show how decadent we were and they said, 'Yeah, we want some of it.'"
The treasure trove of personal stuff includes scripts from the original Dallas TV series, J.R. Ewing's cowboy boots and memorabilia from his other TV hits I Dream of Jeannie, Bewitched and My Favorite Martian.
Hagman is also putting personal antiques, fine and decorative art and furniture up for sale - and there will also be items he collected from his actress mother Mary Martin's career.
The sale, to be held at the prestigious Julien's Auctions Gallery in Beverly Hills, will take place on 4 June (11).
All the items were stored at Hagman's hilltop estate Heaven, which he built in 1991.
Among the art pieces is an 18th century Spanish Colonial painting of the Madonna and Child and works by Barton Benes and Bruce Killen, while the antiques include an Italian credenza, a Rosewood Regency drop leaf table and a set of 10 Chippendale-style dining chairs with needlepoint upholstery.
Also up for grabs are a custom-made mounted parade saddle, a pair of monogrammed boots Hagman wore as Ewing in Dallas, and items from his collection of guns and knives.
The diminutive blonde played Lucy Ewing, niece of scheming oil baron J.R. Ewing, on the hit programme from 1978 to 1985 and again from 1988 to 1990.
Bosses at U.S. TV network TNT announced last year (10) they are remaking the show after plans for a big screen movie version fell through.
Original stars Larry Hagman, Patrick Duffy, and Linda Gray have signed up to reprise their roles as J.R., Bobby Ewing, and Sue Ellen - and now Tilton is pitching for Lucy to be included in the revamp following an internet campaign for the character's return.
She tells TVLine.com, "I read the script for the first episode (of the reboot) and it is absolutely wonderful. It's going to be fabulous... They've gotta bring me back! People have sent me internet petitions to bring her back, and I'm like, 'Oh my gosh, thank you!'"
The actor guzzled champagne on set while playing scheming oil baron J.R. Ewing in the long-running drama series, but he was forced to give up booze after developing liver disease.
Hagman is now preparing to begin work on the upcoming Dallas revamp, and admits it'll be a completely "different" experience playing his character without a buzz.
He says, "It'll probably feel different being sober on the set of Dallas but I've had 15 years' experience of sobriety. Maybe the booze made me a better actor but I'll be fine without it.
"It was boredom that drove me to drink, the tedium during those long waits between takes while the next shot was being set up. Now I've learned to fill those breaks with friends, with charity work, with phone calls, so it's not so bad.
"I did miss drinking for a while but sobriety isn't hard when you consider the alternative. Doctors had given me two months to live when they cut me open. When they looked inside they found I had only two weeks left."
The actor has signed up to play oil tycoon J.R. Ewing's nephew in the update of the hit 1980s soap.
He'll reportedly join Julie Gonzalo and Josh Henderson as the cast for the new show takes shape.
Original Dallas stars Larry Hagman, Linda Gray and Patrick Duffy will revive their old roles as J.R., Sue Ellen and Bobby Ewing in the new show.
The 79 year old has agreed to reprise his role as J.R. Ewing, the ruthless oil tycoon he played in all 13 seasons of the TV hit, for a forthcoming revamp.
But Hagman is incredulous after learning executives are scouting new locations to film the pilot episode.
He says, "I can't believe this is even up for discussion. I'd be less than thrilled if it was not shot there. I mean, come on people - it's called Dallas for a reason."
The cast and crew of the original series filmed on location in Dallas, as well as in studios in Los Angeles.
The actor played ruthless oil tycoon J.R. Ewing in all 13 seasons of the TV phenomenon but recently admitted he wasn't sure if he wanted to return for the new update.
He said, "I don't know if it's worth it. I'm thinking about it. I'd like to know who's doing it, who's writing it and who's in the show. I don't want to work every day and I'd like not to have to promote it. So, we'll see."
But bosses at U.S. network TNT have persuaded the veteran actor to make an appearance - producers have confirmed to the BBC that Hagman has signed a deal.
Original stars Patrick Duffy and Linda Gray will also return.
The actor, most famous for his role as greedy oil baron J.R. Ewing in the soap opera, was devastated when his wife of 55 years Maj Axelsson developed the degenerative brain disease, which robs patients of their memory.
Hagman has since moved Axelsson into a care home to receive professional treatment, but insists his wife has retained her "vivacious" spirit and still recognises him.
He tells Britain's Hello! magazine, "She has had it for six years but we didn't know that until we looked back on her personality changes and traits.
"She still knows who I am. She's always saying, 'Get me out of here!' I say, 'Well, I can't do it myself any longer.' I can't. I just couldn't. I see her every day when I'm here and when I'm gone she knows, but she forgets... It's an awful disease. There's no rhyme or reason. It's devastating. B***dy awful... She was very vivacious and still is."
The actor starred as greedy oil baron J.R. Ewing in all 13 seasons of the hit show, but he's not sure if he wants to take part in a modern TV update.
Hagman admits he could be tempted to join the cast, but only if he didn't have to work daily or promote the show.
He tells Britain's Hello! magazine, "I might be interested. Look, 13 years (of the show) is nice and I got plenty of money. To do it again and risk the legacy I've established... I don't know if it's worth it. I'm thinking about it.
"I'd like to know who's doing it, who's writing it and who's in the show. I don't want to work every day and I'd like not to have to promote it. So, we'll see."
The veteran actor, who played ruthless oil tycoon J.R. Ewing in the hit 1980s TV show, took action against company bosses in May 2009 after an unspecified incident with his Citigroup accounts and a life insurance policy he purchased through the bank.
He accused Citigroup executives of a breach of fiduciary duty, a breach of contract, fraud by misrepresentation and omission, failure to supervise and violation of federal and state law.
He filed for damages of $1.35 million (£900,000) but was given the inflated amount after arbitrators at independent securities regulator FINRA found Citigroup heads had "engaged in serious misconduct", therefore qualifying Hagman to receive punitive damages too.
Hagman was handed $10 million (£6.6 million) in punitive costs, $1.1 million (£733,330) in compensatory damages, and almost $440,000 (£293,330) in legal fees.
Citigroup spokesman Alex Samuelson says, "We are disappointed and disagree with the panel's finding. We are reviewing our options."