'Game of Thrones' star Maisie Williams sent out an adorable birthday wish for BFF Sophie Turner

Maisie Williams has wished her Game of Thrones co-star Sophie Turner on her 21st birthday.

The 19-year-old actress, who plays younger sister, Arya to Turner's Sansa Stark in the HBO's fantasy drama TV series, took to Twitter to express her love for the birthday girl.

"Happy 21st Birthday @SophieT... Forever looking up to you, in more ways than one," Williams tweeted.

Happy 21st Birthday @SophieT
Forever looking up to you, in more ways than one pic.twitter.com/43cCih2KeJ

— Maisie Williams (@Maisie_Williams) February 21, 2017

She posted an old picture where she can be seen in awe of Turner, as an actor and an individual perhaps.

The two on-screen sisters share a warm relationship and have been often seen spending time with each other off-camera too.

The seventh season of Game of Thrones is likely to premiere in mid-2017.