While the opening instalment divided fans, with some loving the somewhat unlikeable characters, others described the pace as too slow. However, viewers agreed on one thing: that Agents of Shield star Iain De Caestecker stole the show as a young incarnation of Tom Hollander's character, Douglas.
WATCH: Us has finally premiered on BBC One - are you enjoying it?
One person wrote: "I have so many questions about Iain De Caestecker's accent for #Us. First, HOW. And follow up to that HOW... did he get his accent/voice to match Tom Hollander's so exactly? H O W." Another person added: "Watching #Us gotta say Iain is a great actor. Loved the dinner scene, laughed out loud and gotta love that he's a scientist again. Plays those roles really well."
Fans were full of praise for Iain's performance in the show
A third person tweeted: "To all the people discovering Iain De Caestecker because of him playing young Tom Hollander in #Us, welcome. Now give him some awards please."
Iain, who is perhaps best known for his role as Fitz in Agents of Shield, opened up about taking on the new role to BBC, explaining: "I play Douglas in his younger years. Whereas Douglas and Connie in present-day are struggling with the idea of the end of their marriage, the flashbacks into the younger Douglas and Connie show how they first met and the origins and context of their relationship. And, ultimately, how they got to the place where they are when we find them at the start of the story in the present day.
Tom Hollander stars in the TV show adaptation
"One of the interesting things about young Douglas is that on the surface, and perhaps unlike Connie, he hasn’t changed so much from then until now. But, the more we learn, we see that Douglas has actually changed more than he realises."
Like this story? Sign up to our newsletter to get other stories like this delivered straight to your inbox.