Emilia Clarke and Iain Glen

Weeks before Game of Thrones will premiere on HBO, fanboys of George R. R. Martin's enormously popular fantasy books are already worrying about how the show is going to end. The author recently told The New Yorker he doesn't want to "do a Lost" and mess up the ending.

Series executive producers D.B. Weiss attempted to further calm their nerves, telling TVGuide.com, "We've talked through what the final episode, the final season will be." Executive producer David Benioff adds: "We can't wait to write that episode. Of the many different fears we have about the show, long-term momentum is not one of them. We're very confident."

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It may seem like a premature concern, after all, HBO has yet to commit to additional seasons.

Blame the vocal — and mostly frustrated — fans of Martin's A Song of Ice and Fire fantasy novels on which the HBO series is based. They've been waiting six years for the fifth book to be released. (Martin has announced it will be out in July, really!). With an increased wait between each novel, fans nerves are frayed. What's more, many have expressed the worry that the 62-year-old author won't live to finish writing the entire seven-book cycle as promised — or that he'll rush to wrap it up in an unsatisfying way.

Hence, Martin's comment about Lost. The author said he's sticking with his unhurried pace because he doesn't want to disappoint his fans like he was disappointed by the ending of the ABC series. As he told The New Yorker, "We watched it every week trying to figure it out... and then I felt so cheated when we got to the conclusion. I want to give them something terrific. What if I f--- it up at the end? What if I do a Lost? Then they'll come after me with pitchforks and torches." (Elsewhere in the world, Lost co-creator Damon Lindelof wasn't too happy to have an unsatisfying ending equated with pulling a Lost — and made it known on his Twitter account.)

With HBO adapting the first novel into a 10-episode season, that worry now includes the TV series.

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"I think it's a legitimate concern because it's potentially 60-70 hours of your life you're investing," Weiss says. "It's fair to want to know that there's somebody at the wheel and that it's going to lead you to a place where you feel that ultimately it was worth investing that time."

Fortunately for fans, Martin has been serving as an available advisor for producers, and they say the partnership, however loose, has given them inside knowledge about what lies ahead for Jon Snow, Daenerys and the other denizens of Westeros. "George has proven through the discussions we've had that he's always known in the rough, broad strokes where this is going to end up," Weiss says."And we think it's going to end up in a way that is uniquely satisfying."

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"It's not some 'it was all a dream' story," Benioff clarifies. "It's not an M. Night Shyamalan movie where there's a massive twist at the end. It all actually makes sense. You can kind of feel in the roughest sense where it's moving towards. It's going to a fantastic place."

Working with Martin comes with another perk as well: They don't have to wait till July to read the fifth A Song of Ice and Fire novel.

"We got the first 600 pages of A Dance With Dragons early from George," Benioff reveals. "Getting to read that is incredible. It's so much fun, but it's also really helpful for us because George had created such an immaculate beautiful world and we want to make sure that if there are going to be major developments in future seasons, we make sure we seed it properly in the first season."

Game of Thrones puts Martin's master plan in motion on Sunday, April 17 at 9/8c.

Do you think Martin will complete his series satisfactorily? Is it too early to worry about the TV show's fate?