Billie Lourd Posts Touching Tribute to Late Grandmother Debbie Reynolds for Her 86th Birthday

Billie Lourd is remembering her late grandmother Debbie Reynolds on what would have been her 86th birthday.

The American Horror Story: Cult actress, 25, shared a throwback photo of herself with her late grandmother on Sunday, which would have been the Singin’ in the Rain star’s 86th birthday. Lourd’s mom, Carrie Fisher, is also pictured in the photo, resting her head on Lourd’s arm and Reynolds’ shoulder.

She captioned the photo with a series of emojis, including stars, crowns and a heart.

Reynolds died in Dec. 2016 after suffering a stroke, just a day after Fisher died of a heart attack at the age of 60. Last year, Lourd spoke to Ellen DeGeneres about the hardships of adjusting to life without her mom and grandmother.

“It’s completely surreal,” she said. “There’s no way to really explain it — it’s so hard to talk about. If I say I’m doing good, I’m too happy. If I say I’m not doing good, then I’m a mess. So it’s really hard to know what to say about it because it’s so surreal and impossible to deal with.”

To get through both losses, Lourd told Town & Country she remembered her mother’s sense of humor.

“If life’s not funny, then it’s just true – and that would be unacceptable,” Lourd said. “Even when she died, that was what got me through that whole thing. When Debbie died the next day, I could just picture her saying, ‘Well, she’s upstaging me once again, of course – she had to.’ ”

After toxicology reports showed Fisher had drugs in her system at the time of her death, Lourd addressed her mom’s battle with drug addiction and mental illness in an exclusive statement to PEOPLE, saying Fisher would “want her death to encourage people to be open about their struggles.”

“Tons of people grow up with mentally ill parents who have drug problems… It’s such a common thing, and people really don’t talk about it, ” she said about why she decided to make the statement. “It ultimately helped so many more people.”