Davies, who worked on the revival of the hit BBC sci-fi show from 2005 to 2010, is returning to the show for new episodes later this year.
A new image shared ahead of Doctor Who’s forthcoming 60th anniversary specials gave fans a first look at guest star Jonathan Groff, as well as new looks for Ncuti Gatwa’s Doctor, and Ruby Sunday (Millie Gibson).
Davies shared the picture on his Instagram accout, alongside an emoji-heavy message.
Among the symbols used in the caption was a “potato” emoji – prompting fans to speculate that he was cryptically teasing the return of the Sontaran alien race.
In Doctor Who, Sontarans are a ruthless warrior group of humanoid aliens with dome-shaped heads, who first appeared back in 1973.
They have previously been described in the show as “huge potatoes with ray guns”.
Fans shared their theories in the comments underneath Davies’s post.
“POTATO? SONTARAN?” one person asked. “Regency was also 19th century, Paternoster Gang??? RUSSELL?! I am obsessed either way, the c19th gal I am is VERY HAPPY OMG.”
“SONTARANS????” someone else simply wrote.
“I’ve seen a few people on the timeline suggest Sontarans,” one fan added.
Another fan wrote on Twitter: “I wouldn’t mind seeing the Sontarans return for this series, to be honest. They were very well done during [2021 Doctor Who miniseries Flux] and I’m sure there is a lot of story potential. I wonder how RTD would manage them this time around. I hope they keep the designs from Flux.”
Doctor Who returns to BBC One later this year.