Westworld star Luke Hemsworth found out about the show's cancellation on his birthday: 'F---!'

"Happy birthday, Luke Hemsworth! Your show is canceled." Not exactly the surprise the actor was hoping for on his special day.

Hemsworth has revealed that he found out about the cancellation of Westworld on his 42nd birthday earlier this month.

"I was like, 'F---! Dammit!'" he told Entertainment Tonight at the premiere of his brother Chris Hemsworth's show Limitless. "You hope these things go forever, but everyone's got their own reasons. I'm very thankful for my part in that series, and that journey was a big part of my life, but yeah, it was disappointing."

Hemsworth played Ashley Stubbs, who initially worked security at the titular robot-operated Westworld park at the center of the HBO sci-fi series until it was divulged that — spoiler alert! — he was a robot himself.

John Johnson/HBO Luke Hemsworth in a scene from 'Westworld'

The futuristic show, which regularly featured trippy twists through its exploration of humanity's dependence on technology, focused on the highly realistic Western-pegged adult theme park in which wealthy "guests" could pay top dollar to live out their fantasies. Humanlike A.I. creations — portrayed by stars like Evan Rachel Wood, James Marsden, and Thandiwe Newton — were programmed to execute story arcs for visitors' amusement, until they broke free of their computer engineering.

Season 4 of Westworld finished its run in mid-August. Series creators Jonathan Nolan and Lisa Joy had planned for a fifth and final season to wrap things up.

"We never broke [the show] with an exact number of seasons left," Joy told EW in an interview pegged to the season 4 finale, "but then when we were writing this season, we were like, 'We can get it up to the precipice before we round it out with what we had always planned would happen in the fifth season.' So we have, like Dolores, one more story to tell — and whether we get to tell it, we'll see."

Under new leadership at Warner Bros. Discovery, HBO opted to cancel the series. "Over the past four seasons, Lisa and Jonah have taken viewers on a mind-bending odyssey, raising the bar at every step," a spokesperson said in a statement. "We are tremendously grateful to them, along with their immensely talented cast, producers and crew, and all of our partners at Kilter Films, Bad Robot, and Warner Bros. Television. It's been a thrill to join them on this journey."

Hemsworth told ET, "I think the idea right from the start was to go full circle and come back to be about loops, to be about human beings and robots being stuck in that trajectory. Unfortunately, we get cut off, but it's the nature of the world. You can't get depressed about it. You move on, and it opens up new doors."

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