The actress uploaded to Instagram on Tuesday a photo of Kingston watching the film, which famously stars Fisher as Leia Organa.
Kingston is wearing a knitted hat that resembles Leia's iconic hairstyle and a onesie that features Leia and flowers.
Star Wars Day takes place every year on May 4, as fans around the world celebrate everything related to the sci-fi adventure series. Disney+ has released a new animated series titled The Bad Batch featuring clone troopers who defy the Empire to mark the occasion.
Fisher died at the age of 60 in December 2016 following a heart attack. Debbie Reynolds, Fisher's mother and Lourd's grandmother, died one day later at the age of 84. Fisher and Lourd starred together in the most recent trilogy of Star Wars films.
Lourd announced the birth of Kingston with her fiancé, Austen Rydell, in September. Lourd had kept her pregnancy a secret.