Debbie Reynolds will always have a special place in Billie Lourd's heart.
The Scream Queens star took to Instagram on Saturday to pay tribute to her "Abadaba" on what would've been the actress' 85th birthday.
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"??? Happy 85th to my constantly classily clad Abadaba ?," Lourd wrote alongside the pic, which features an emerald green-clad Reynolds, while Lourd's mother, Carrie Fisher, poses behind her.
Reynolds' nickname comes from her and Carleton Carpenter's cover of the song "Aba Daba Honeymoon" from their 1950 film, Two Weeks With Love.
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Reynolds and Fisher were honored by friends, family and fans at a public memorial last week, though Lourd did not attend the festivities.
"Billie is 24 years old. She's dealing with two gigantic losses," Reynolds' son and Fisher's brother, Todd Fisher told ET ahead of the memorial. "These two girls -- my girls, my mother and my sister, were big, big personalities [with a] big influence on Billie, myself, many people."
"There's a vacuum in the room and she's feeling it and we're all feeling it. It's just that I'm 59 and I have no choice but to step up and put this stuff forward," he shared. "I'm letting [Billie] breathe, you know? She needs to breathe. She needs to step back from all of this loss."
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See more in the video below.