Ray Richmond contributes to Deadline’s TV coverage.

Downton Abbey has become famous for killing off its characters whose actors have come to the end of their three-year deals – most traumatically Matthew Crawley (played by Dan Stevens) at the end of season three, devastating viewers on both sides of the Atlantic. But there is really only one Downton-ite whose demise would be utterly catastrophic: co-creator and sole writer Julian Fellowes. The unthinkable was pondered tonight during a jam-packed event at the TV Academy designed to drum up some Emmy enthusiasm for the Masterpiece costume drama/soap. It had been revealed in February that Fellowes had signed on to write and produce the NBC period drama The Gilded Age. The question tonight was whether Fellowes could work on both shows simultaneously if it came to that. Answer: No.

Related: Will Julian Fellowes Leave ‘Downton Abbey’ If NBC’s ‘Gilded Age’ Is A Go?

So then, asked moderator Pete Hammond of Deadline, when might Downton be ending? “Well,” replied Fellowes, “we’re always reading in the papers when it’s ending, but we don’t know when it’s ending ourselves so how can some journalist know? I think it’s still got some legs to it.” While that’s somewhat of a coy answer, Fellowes admitted earlier this year that it’s possible he might need to devote himself full time to Gilded Age while leaving the Downton writing duties to others. Tonight, he reiterated that the new series – if it comes at all – would start up after Downton ends. After the panel, he was asked if he might have to leave Downton before it concludes its run if the two series were to overlap. “I would answer that if I could,” he said. “I simply don’t know. Because we don’t have an end date. The newspapers keep saying we do, but we don’t. The question is how long will they wait for Gilded Age, and when will Downton finish up, and we just don’t know those answers right now.” But if Fellowes had to choose between the two shows, which would get the nod? He smiled before replying, “Oh, I couldn’t answer that.”

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The good news for Downton fans is that any day of reckoning isn’t imminent. The series is poised to launch its fourth season on Jan. 5 looking very much like a program in its prime. It’s the highest-rated drama series in PBS history, wrapping season three on Feb. 17 with 8.2 million viewers. And while six new actors are joining the cast for season four, Shirley MacLaine is returning for her second campaign – and Dame Maggie Smith will be back as well. Neither Smith nor MacLaine (nor fellow lead Hugh Bonneville) was in attendance tonight. But the event did feature Fellowes, exec producer Gareth Neame and castmates Elizabeth McGovern, Michelle Dockery, Phyllis Logan, Rob James-Collier, and Joanne Froggatt. Hammond presided over a spirited discussion that drew a turnaway crowd. Reportedly, nearly 1,000 academy members RSVP’d for an event that could fit little more than half that. There wasn’t an empty seat to be found, which couldn’t be said for the Mad Men event the night before. Fellowes, a charming storyteller and natural raconteur, effortlessly dominated the panel. However, the best line of the night – a single word — was uttered by McGovern. While Dockery was marveling at the “extraordinary life” that MacLaine has had, McGovern corrected her: “Lives.”