Billie Lourd Remembers Late Mom Carrie Fisher on What Would've Been Her 66th Birthday

Actress Carrie Fisher and daughter actress Billie Lourd attend the Premiere of Walt Disney Pictures and Lucasfilm's 'Star Wars: The Force Awakens' on December 14, 2015 in Hollywood, California.
Actress Carrie Fisher and daughter actress Billie Lourd attend the Premiere of Walt Disney Pictures and Lucasfilm's 'Star Wars: The Force Awakens' on December 14, 2015 in Hollywood, California.
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Billie Lourd is opening up about grieving her mom Carrie Fisher on what would have been the Star Wars actress' 66th birthday.

On Friday, Lourd, 30, posted a tribute to her late mother, who died Dec. 27, 2016, at the age of 60.

In the Instagram post, Lourd shared a sweet throwback photo of herself with Fisher and wrote, "My Momby would have been 66 today. I woke up this morning feeling like I should write some long wise grief advice caption like I know what the f--- I'm talking about."

"But then I realized, even after 6 years, I still have no formula or map on what to do on days like these," she continued.

"You can never be an expert in grief," said Lourd. "It is forever changing — the ultimate shape-shifter. And you never feel like you know exactly what to do or feel. And that's okay. Whatever you feel is okay. Sending my love to all the griefers (yet another Billie Lourd petition to make this a real word) out there. You are not alone."

RELATED: Carrie Fisher's Life in Photos

Mark Hamill and Carrie Fisher attend the Midnight Mission's 100 year anniversary Golden Heart Gala held at the Beverly Wilshire Four Seasons Hotel on September 30, 2014 in Beverly Hills, California.
Mark Hamill and Carrie Fisher attend the Midnight Mission's 100 year anniversary Golden Heart Gala held at the Beverly Wilshire Four Seasons Hotel on September 30, 2014 in Beverly Hills, California.

Araya Diaz/Getty

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Fisher's Star Wars franchise brother Mark Hamill also posted a tribute to his late friend. Along with an assortment of pictures from their past, Hamill tweeted simply: "For Carrie: 🎂."

Lourd spoke with PEOPLE at the Los Angeles premiere of Ticket to Paradise on Monday, where she opened up about her busy work schedule throughout her second pregnancy. The American Horror Story actress, who shares 2-year-old son Kingston Fisher with husband Austen Rydell, said being pregnant and parenting a toddler while working has been "hardcore."

She also noted that her mother did not work during her pregnancy, which is what inspired Lourd to do so.

"That would've been incredible. And that's why I also wanted to do it," Lourd explained. "Because it will be cool for this kid to be able to Google it and see themself."