Doctor Who season 8 has made its worldwide debut tonight.

The opening episode premiered on BBC One on Saturday, with Peter Capaldi taking on the role of the popular series;12^th Doctor. The premiere episode was 80 minutes long, entitled "Deep Breath."

Capaldi's performance has been praise, with The Mirror's Richard Beech calling it "all the hallmarks of a great Doctor" and The Guardian's Euan Ferguson hailing his performance as "wise and thoughtful."

"He absolutely failed to nail the character completely, and for that we should be immensely heartened, given how much good it bodes for the rest of the series," said Ferugson.

"If you watched Deep Breath and you don't want to watch the rest of series 8, then there truly is something wrong with you," said Beech.

Variety's Geoff Berkshire wrote: "What Capaldi lacks in youthful energy, he more than makes up for in gravitas and wry eccentricity, whether marvelling at his "independently cross" eyebrows or gleefully embracing his Scottish accent as a license to complain."

Despite the overall positive reaction to Capaldi's performance, some critics have criticized the plot.

Ferguson called the plot "demented" and fans took to Twitter to share their thoughts. One fan said, "Seriously disappointed with Doctor Who. Bored, angry, frustrated, irritated, offended and let down. Wow."

Doctor Who season 8 episode 1 synopsis is as follows:

"When the Doctor arrives in Victorian London he finds a dinosaur rampant in the Thames and a spate of deadly spontaneous combustions. Who is the new Doctor and will Clara's friendship survive as they embark on a terrifying mission into the heart of an alien conspiracy? The Doctor has changed. It's time you knew him."

The premiere episode can be watched online via live stream on HULU.