The 'Game of Thrones' star and the former Jonas Brothers member - who got engaged in October 2017 - revealed on Instagram their new co-coordinating inkings, which pay homage to their respective family members.
Sophie, 21, showed off her tattoo first, posting a photo of a simple initial of the letter 'g' on her pinkie finger in calligraphy.
She wrote: @mr.k_tattoo for my grandad. My hero. [sic]''
Fans loved the tattoo and the 'X-Men: Apocalypse' actress was flooded with positive comments.
One fan wrote: ''Love the tattoo ... very nice, very simple but yet it looks very meaningful!!!! [sic]''
Joe posted a picture of his larger tattoo a day later and 'The Voice' judge decided to go for a black and white portrait in the style of a postage stamp with the initials ''PA''.
He wrote: ''For PaPa Miller. Thank you @mr.k_tattoo. [sic]''
Joe was also praised by fans for his tattoo, one wrote: ''@joejonas I love it!!! looks like he was an amazing person!!! U look a little bit like him. [sic]''
Another said: ''Amazing tribute to an amazing man. Who helped create your wonderful mother @mamadjonas and in turn ... helped create ... you. [sic]''
This isn't the first time Joe has decided to get a sentimental tattoo; in April he got a portrait of what appears to be Sophie on his forearm.
Sophie isn't the only 'Game of Thrones' member who'll be sporting some ink, co-star and best friend Maisie Williams is planning on getting a tattoo in tribute to the HBO show.
Sophie has starred as Arya Stark in the hit fantasy drama and she has revealed she will be getting some body art dedicated to her beloved character.
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