Lourd, 24, posted a throwback photo to Instagram, captioned only with a black heart.
In the snap, the young Scream Queens actress sits on smiling Fisher's lap, subtly sticking out her tongue for the camera.
Meanwhile, a bitter family feud has erupted following the shocking deaths of Fisher and her mother, Lourd's grandma, Debbie Reynolds.
The 84-year-old Singing in the Rain superstar tragically passed on Dec. 28, just a day after her daughter died.
"While Debbie lost many millions in her lifetime to scheming husbands and bad business decisions — and even went bankrupt — she was worth a fortune when she died," a source told Radar. "She left the bulk of her $70 million estate to her children with Eddie Fisher, Carrie and Todd, and Billie Lourd.
"She never thought for a minute that Carrie would die before her and didn't plan for it. Then Debbie herself passed away so suddenly before changing her will," the insider continued. "I'm told Billie — Carrie's only child — believes her mother's share should pass straight to her."
That's because if Debbie had died first, Carrie would have received her inheritance — and when Carrie passed, it would have gone to Lourd, said the source.
"But Todd thinks Carrie's share should go to him as Debbie's only surviving direct descendant. Friends are bracing for a family war. It's so sad. Debbie would be devastated."
Billie will inherit Carrie's $5 million estate, according to insiders.
The family feud was apparent at the public memorial service for Debbie and Carrie, say sources.
Lourd shockingly boycotted the event — opting to spend time with her boyfriend, actor Taylor Lautner, and her father, Bryan Lourd.
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