HBO has booked a return ticket to Westworld.

The premium cable network has renewed the freshman drama for a second season of 10 episodes to air in either fall 2017 or 2018, The Hollywood Reporter has learned. (Also scoring sophomore seasons are comedies Divorce and Insecure.)

" Westworld is such a big, ambitious show. I don't know if it will be fall of 2017 or into '18," HBO programming president Casey Bloys told THR . "That will depend as we get up and running. With Westworld , because the production is such a big endeavor, I don't exactly know when [it will premiere] yet. I can't speculate other than to say it'll either be '17 or '18. Probably more like '18 and half-hours [Insecure and Divorce] in '17 but we're a year away so let's see how it goes."

The star-studded sci-fi Western about a futuristic amusement park where visitors live out their wildest fantasies in a world populated by robots came in with high expectations — and a budget in the $100 million range for its first 10-episode season.

The series opened to a promising start Oct. 2 with nearly 2 million viewers tuning in live-plus-same-day for the supersized premiere. Factoring in HBO Go and HBO Now streams, that spikes to 3.3 million total viewers. All told, an estimated 6 million watched the debut, including on-demand and multiple network plays. Episode two, offered early on streaming and VOD platforms to subscribers, scored a combined 2.7 million viewers. The drama, which has taken a live-plus-same-day hit when airing against AMC juggernaut The Walking Dead, has made up that difference on DVR and on-demand/HBO Go returns. Season to date, Westworld is averaging a gross audience of 11.7 million total viewers — besting Game of Thrones and True Detective during their comparable first-season frames.

"We’re thrilled that the saga of Westworld will continue for another season,” co-creators/showrunners Jonathan Nolan and Lisa Joy said in a statement. "During the lengthy journey to the screen, our incredibly talented actors, staff and crew became a family, and we look forward to the privilege of continuing this experience with them. We’re also thankful to all of our amazing partners at HBO, WBTV and Bad Robot for their steadfast support, imagination and ambition. We simply couldn't have made this show anywhere else."

Based on the 1973 Michael Crichton movie and produced by corporate sibling Warner Bros. Television with J.J. Abrams and the late Jerry Weintraub among its exec producers, Westworld had a long journey to the screen. Picked up to pilot in August 2013 and ordered to series in November 2014 under former HBO programming president Michael Lombardo, the futuristic Western originally was eyed for a 2015 debut. The ambitious series was the subject of swirling rumors about its messy production process for months. The show ultimately was shut down from Dec. 1, 2015, to Feb. 1, 2016, to allow Nolan and Joy time to catch up on scripts, with the drama rumored at one point to be pushed to 2017. Sources say it was Nolan who fought for the production to get up and running again so the series did not lose its California tax credit.

The breakout ratings and critical response to Westworld comes at a key time for HBO, which is facing a turning point in its history. Lombardo, a 33-year veteran of the cabler, exited in May with former head of comedy Bloys taking over as programming president. The network, with its well-known deep pockets, also is facing steep competition as its 15-year streak atop the Emmy leaderboard is in jeopardy thanks to the likes of FX and Netflix. What's more, the end is in sight for back-to-back Emmy outstanding drama winner Game of Thrones. The most-watched program in the channel's history will sit out the 2017 Emmys as production will start later to feature winter weather to match its creative story.

"This is 100 percent a sigh of relief," Bloys told THR on Monday. "What I really feel is happy that creators of these shows put them out, wanted to say something and the good news is each show raised the questions that creators wanted to raise and talk about and they all did what I believe the creators hoped they would do."

With the $100 million Vinyl disappointment (one of Bloys' first moves was to scrap its planned second season) and two David Fincher projects that both stalled due to creative differences, the pressure was certainly on Westworld to perform. In the interim, Westworld along with The Night Of, Divorce and Insecure — as well as the upcoming debuts of Big Little Lies and David Simon's The Deuce — will look to keep HBO atop the Emmy leaders.

"Westworld for us is a great building block to have as we think about the ongoing drama series," Bloys noted. "We've got [limited series] The Young Pope, Big Little Lies and Sharp Objects, but the ongoing drama series, this is a really big and important building block for us. When you look at the breadth of our programming, the ongoing drama series is what the media have all been documenting, trying to get an ongoing drama series going. This is a really big deal for us."

Westworld, which was criticized early on for its violence against women, features a cast of A-listers including Anthony Hopkins as the head of an ultra-realistic amusement park where visitors come to live out their most outrageous desires. The cast also includes Evan Rachel Wood, James Marsden, Thandie Newton, Jeffrey Wright and Ed Harris. (Hopkins and Harris are said to have scored $175,000 per episode each, with the latter potentially having only a two-year deal.)

For his part, Bloys remained tight-lipped as to whether all of the Westworld stars will return for a second season. "I don't want to speculate about cast because there's still three episodes left to air," he said.