Earlier this year, it was confirmed that Hagman, Linda Gray and Patrick Duffy had all signed on to reprise their roles from Dallas in a continuation focusing on a new generation of characters.
"Filming was so fabulous," Hagman told E! Online. "It was just amazing. It was surreal, fun, nostalgic, everything. Everything rolled into one.
"And reuniting with Larry and Patrick, quite something," he added.
Linda Gray also teased what fans can expect to see when Sue Ellen returns on the new series.
"I'm single," she revealed. "I'm very rich, richer than J.R. Ewing, and I have a gorgeous car. But I don't have a house. So that's where Sue Ellen is right now."
Hagman noted that the cast had no expectations about the success of the reboot, claiming that it would be difficult for them to attain the popularity that they had during the show's original run.
Charlene Tilto and Steve Kanaly will also return for the new series, alongside new cast members Brenda Strong, Jesse Metcalfe, Julie Gonzala, Josh Henderson and Jordana Brewster.
TNT will make a final decision on whether to order a full season of the new Dallas after viewing the show's pilot episode.