The legendary sex-and-scandal soap was revived in 2012 after 21 years off air but it was announced earlier this month (Oct14) that bosses at America's Tnt network will not be commissioning a fourth season.
Fans have launched a 'SaveDallas' campaign on Twitter.com to force a reversal of the decision or encourage another network to pick up the show, and now some of its leading stars are joining the fight.
Duffy, who played Bobby Ewing in the original run and the revamp, told fans on the microblogging site, "I for one am not done with Bobby Ewing! Let's see if some network wants the Ewings to live on! Love you all!!... The Save Dallas surge is fantastic everyone. Let's keep going. I'm feeling All Ewing all over again."
His co-star and close friend Gray, who played Sue Ellen Ewing, posted links and contact information to help the campaign, writing, "Missing seeing my favorite actors each week #SaveDallas!"
Henderson, who played the son of backstabbing oil magnate J.R. Ewing in the show, and fellow Dallas star Brenda Strong have also shown their backing for the campaign by re-tweeting messages from fans to help spread the word.