Drama series Westworld will return for potential fourth and fifth seasons, HBO has revealed.

Casey Bloys, the network's programming head, confirmed that show creators Jonathan Nolan and Lisa Joy had already signed on the dotted line for future installments of the Western sci-fi series.

In April, it was announced Nolan and Joy had signed a huge overall deal at Amazon, exiting their previous agreement with Warner Bros Television, which produces Westworld.

According to Bloys, the new deal shouldn't be a problem.

"They are 100 percent hands-on. We have deals with them for a potential fourth and fifth season. So the deal with them (at Amazon) is for, I believe, everything but Westworld."

"And they're very committed to 'Westworld'. So I'm not worried about losing their focus, they don't lose focus," the senior executive has been quoted as saying.

Bloys also said the third installment, The New World, will premiere sometime in the first half of 2020.

HBO is yet to announce a premiere date for season three.