Luke Hemsworth is opening up about Westworld getting shut down.

The actor, who has played head of security Ashley Stubbs since the sci-fi series launched in 2016, spoke to Entertainment Tonight on Tuesday about HBO’s surprise announcement last week that Westworld had been canceled after four seasons.

“You hope these things go forever, but everyone’s got their own reasons,” Hemsworth told the outlet at the premiere for brother Chris Hemsworth’s new Disney+ series, Limitless. “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 explained that what made matters worse was that he got the bad news of the cancellation on his 42nd birthday: “I was like, ‘Fuck! Dammit!’”

He went on to say that he was hopeful for what might have been in store for fans with a fifth season. “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,” Hemsworth continued. “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.”

HBO’s decision to end the expensive Emmy-winning series from co-creators Jonathan Nolan and Lisa Joy followed a sharp decline in linear ratings for season three; this trend continued into season four, for which the final episode aired in August. In a statement about the cancellation, HBO said it was “tremendously grateful” to Nolan and Joy, along with the “immensely talented cast, producers and crew.”

Hemsworth’s co-stars in the series included Evan Rachel Wood, Thandiwe Newton, Tessa Thompson, Ed Harris, Jeffrey Wright and James Marsden.