Game Of Thrones fans were surprised to see Yara Greyjoy out of her armour and in a dress in new BBC drama Gentleman Jack.

The programme about Regency landowner Anne Lister, who is regarded as the “first modern lesbian”, started on BBC One on Sunday with Suranne Jones in the lead role.

Eagle-eyed viewers soon spotted that Lister’s sister was played by Gemma Whelan, who stars as Yara in fantasy drama Game Of Thrones.

“Seeing @WhelanGemma in a period dress is just strange,” said one person on Twitter.

“To me she’ll always be Yara Greyjoy, Queen of the Iron Islands.

“But she is totally amazing.”

They added: “I offically love Gemma Whelan as the sister, Yara Greyjoy to this, well done.

“She’s nailing this. I want to see her in everything from now on.”

“Not used to seeing @WhelanGemma look so clean, in a dress and wearing colour!” said another viewer, adding the hashtag “#IronIslandsMeetsShibdenValley”.

“Yara Greyjoy scrubs up well,” said another.

Another fan said “seeing anyone who is in GOT in a show that is not GOT is really weird”.

Set in 1832 in West Yorkshire, Gentleman Jack was created by Sally Wainwright and is based on Lister’s diaries.

It follows the landowner as she returns to Halifax from her travels, determined to transform the fate of her family and their faded ancestral home Shibden Hall – and to find herself a wife.

Gentleman Jack continues on BBC One.