Guest actors and a new monster were unveiled in a new trailer for 'Doctor Who: Flux'.

Doctor Who: Flux

Doctor Who: Flux

The hotly-awaited 13th series of the classic sci-fi series will be the last for female Time Lord Jodie Whittaker and showrunner Chris Chibnall - who will be replaced by returning screenwriter Russell T Davies.

And in a new preview for the six-episode serial, it was revealed that the Sontarans, Weeping Angels, Cybermen, and the Ood will all be back for scares, along with the new monster, Karvanista.

What's more, 13 cameo stars were confirmed by BBC One, including Robert Bathurst, Thaddea Graham, Blake Harrison, Kevin McNally, Craig Parkinson, Sara Powell, Annabel Scholey, Gerald Kyd and Penelope Ann McGhie.

'Downton Abbey' star Robert Bathurst said: "People say 'Doctor Who' is science fiction. Fiction? No it's all real, and it's as scary to do as it looks. Great to be part of it."

'The Inbetweeners' actor Blake Harrison said: "It's a pleasure to be a part of this huge show that has such a passionate fan base! I hope all the 'Doctor Who' fans enjoy the new series and my role in it."

'Pirates of the Caribbean' actor Kevin McNally said: "I am thrilled to be helping the Doctor put the universe to rights in the latest season of 'Doctor Who'."

Craig Parkinson of 'Misfits', 'Whitechapel' and 'Line of Duty' fame commented: "I feel tremendously lucky to have joined the 'Doctor Who' family this season. Chris' scripts are witty, intelligent and full of light and shade, making my job as an actor extremely enjoyable! My son loves the show and as long as he gives me his seal of approval I'll know I've done it justice!"

While 'Being Human' star Annabel Scholey gushed: "I am absolutely thrilled to be a part of the 13th series of 'Doctor Who'. It was a lot of fun to film and I enjoyed every minute I spent with the amazing cast and crew...Halloween will be that little bit more spooky this year!"

More names will be added to the cast list in due course, while the above stars' characters are also yet to be announced.

It's already known that Mandip Gill is returning as Yasmin Khan, while there's a new companion in Dan Lewis (John Bishop).

Matt Strevens, Executive Producer, added: "I can't wait for the audience to come on the 'Flux' ride with us. It's our biggest adventure yet with so many brilliant new characters to fall in love with. We had a blast making it."

The new series of 'Doctor Who' airs on BBC One and BBC iPlayer on October 31st.