Hours before the cast of the HBO drama “Succession” gathered for the premiere of its fourth and final season, the news broke: Rupert Murdoch, 92, the chairman of the conservative media empire that owns Fox News, announced in his own tabloid that he was engaged to Ann Lesley Smith, 66, a former police chaplain of San Francisco.

Commenters online noted that it sounded like something out of, well, “Succession,” which portrays the fictional Roy family, a media dynasty locked in an intergenerational power struggle that bears an uncanny resemblance to that of the real-life Murdochs. (Lest there be any doubts, the series grew out of a screenplay entitled “Murdoch.”)

At the screening Monday night at Jazz at Lincoln Center, “Succession” cast members said they were sad the show would be ending and politely dodged questions about how it would conclude. But many were game to discuss Mr. Murdoch and the show’s central conflicts of love, money and power.

Mr. Murdoch has “always been a player,” said Nicholas Braun, whose character Greg stammers on the outskirts of the Roy family. “I hope he’s found the best love yet.”

Brian Cox, who plays the Roy family’s fearsome patriarch, Logan, joined Mr. Braun on the midnight-blue carpet to throw back shots of tequila in mini red Solo Cups.

J. Smith-Cameron, who plays the general counsel Gerri, said she was not surprised by Mr. Murdoch’s late-stage engagement — in part because it sounded exactly like something Logan would do. “He’s this ruthless, really selfish person with a voracious appetite for life and a voracious appetite for riches and everything that goes with it,” she said of the Waystar Royco executive. “That power has really gone to his head.”

The announcement of Mr. Murdoch’s engagement came a day before Fox News was set to present oral arguments in the $1.6 billion defamation suit brought by Dominion Voting Systems. The suit, which is expected to go to trial next month, accuses Fox of knowingly spreading false information about the 2020 presidential election.

That timing did not seem coincidental to James Cromwell, who went from playing Rupert Murdoch in an Australian stage production of “Rupert” to playing Ewan Roy, Logan’s estranged, anticapitalist brother, on “Succession.”

“It’s all planned — nothing is off the cuff,” he said. “They have the best and the brightest, hundreds of them in a room, thinking up things to do and things to say and things to present to the public that make them seem like they’re not responsible.”

Arian Moayed, who plays the smooth investor Stewy, also questioned the motive behind Mr. Murdoch’s announcement. “This sounds awful, but I don’t know if he’s doing it for love,” he said. “I think it’s a cool little distraction from everything that’s happening over there.”

“Succession” trades in not just twisted business and familial relationships, but in knotty romantic ones, too. There is Roman, the Roy sibling who accidentally texts an illicit picture to his father. There is the triangle of tension between Logan, his wife, Marcia, and his assistant, Kerry. There is Kendall, who invites himself and his professional entourage into his estranged wife Rava’s apartment indefinitely. And there is the strained marriage between Tom and Shiv, Logan’s steely daughter.

Sarah Snook, who plays Shiv, had not heard about Mr. Murdoch’s engagement. “That is bananas,” she said. She mulled over what advice she might give to someone marrying into the Murdoch family or its fictional equivalent. “Run?” she suggested.

The news was also a surprise to Cherry Jones, who plays another media magnate, Nan Pierce. “That old dog!” she said. “I think anyone who chooses to be in that situation certainly has an inkling of what they’re in for.”

Guests collected HBO-branded M&M’s on their way into the theater to watch the season’s first episode. The show’s creator, Jesse Armstrong, took the stage and bid farewell to the cast. “We’ve been such a happy gang,” he said. “I feel rather heartsick.”

Giggles, groans and the rustling of M&M bags could be heard throughout the episode, which set up a final face-off between Logan and his four children (As Mr. Armstrong told The New Yorker, the series’ title contains a promise.)

At the after-party in the nearby Ertegun Atrium, cast members mingled with celebrities and media executives in muted suits and gowns that would slot right into the show’s gloomy-boardroom palette. There were some exceptions: Fran Lebowitz wore jeans, and the “Saturday Night Live” comedian Sarah Sherman wore a long coat embroidered with cannolis.

Matthew Broderick descended a staircase in a black-and-gray plaid jacket, and Jeremy Strong, who plays Kendall and wore a monochromatic brown ensemble with turquoise sneakers, helped himself to caviar served like miniature ice cream cones.

In The New York Post article that broke the news of the engagement, Mr. Murdoch said, “I dreaded falling in love — but I knew this would be my last.” He added: “We’re both looking forward to spending the second half of our lives together.”

Alan Ruck, whose character Connor proposes to his girlfriend in the third season, was less starry-eyed about the whole enterprise. He advised the couple to prepare for the worst: “Prenup,” he said. “Get it in writing.”