The long-running sci-fi favorite Doctor Who is reaching the end of its 12th season and is gearing up for a 13th with the BBC. The season 12 finale will feature a few special guest stars, including Ian McElhinney of Game of Thrones and Steve Toussaint of Prince of Persia: The Sands Of Time.

The upcoming season finale will be a two-part story, with the first episode being titled “Ascension of the Cybermen” and the second being “The Timeless Children.” As you could probably guess from the title, the finale will see the return of the Cybermen, the dangerous robotic enemies that have plagued the Doctor since the first few seasons of the show. The finale is written by Doctor Who showrunner Chris Chibnall, and is one of the first two-part stories Chibnall has developed since taking over the showrunner position from Steven Moffat. In an interview with Deadline, Chibnall mentioned that his goal with the most recent season was to explore new narrative structures. 

As for the guest stars, McElhinney and Toussaint both expressed their enthusiasm for working on the show. “I very much enjoyed my time on Doctor Who,” McElhinney stated. “The team were a delight to work with and everyone was very supportive and welcoming. All in all it was a blast.”

“It was an honour to play a part in the giant of British (and world) TV that is Doctor Who,” Toussaint added. “What’s not to like? I had such a great time working with Jodie and ‘the Fam’; another one off the bucket list.”

Doctor Who Executive Producer Matt Strevens also discussed working with McElhinney and Toussaint. “We were delighted to have Ian and Steve on board the TARDIS for the drama filled two-part finale. Their wide-ranging talent and versatility as actors help bring series 12 to a dramatic conclusion. They were an absolute joy to work with and we can’t wait for viewers to see them in action.”

The 2-part season 12 finale of Doctor Who airs this month on BBC and BBC America. You can watch the season 12 trailer below.