By Devan Coggan
January 02, 2017 at 01:51 PM EST
Jason LaVeris/FilmMagic

After the deaths of both her mother, Carrie Fisher, and her grandmother, Debbie Reynolds, Billie Lourd is speaking out for the first time, thanking fans and friends for their overwhelming support.

The Scream Queens star shared an old photo with her mother and grandmother on Instagram, just a few days after Fisher and Reynolds died within just a day of each other.

“Receiving all of your prayers and kind words over the past week has given me strength during a time I thought strength could not exist,” Lourd wrote. “There are no words to express how much I will miss my Abadaba and my own and only Momby. Your love and support means the world to me.”

Fisher, 60, died unexpectedly on Dec. 27 after suffering a heart attack on board an airplane. Reynolds, her 84-year-old mother, died the next day after suffering a possible stroke.

The 24-year-old Lourd, whose father is Hollywood agent Bryan Lourd, appeared opposite her mother in 2015’s Star Wars: The Force Awakens. On Dec. 12, just a few weeks before Reynolds and Fisher passed away, Lourd stopped by Late Night with Seth Meyers to reflect on growing up with two iconic Hollywood actresses in her family. She told Meyers that although both Fisher and Reynolds initially tried to dissuade her from pursuing acting, they were overwhelmingly proud of her accomplishments, adding that Reynolds even had a suggestion for how Lourd should be referred to in Hollywood.

“She gets really upset when I get called ‘Carrie Fisher’s daughter,’” Lourd told Meyers at the time. “She wants people to call me ‘Debbie Reynolds’ granddaughter.’ It’s very offensive to her. She does not like to be cut out — not at all.”

After the news broke that both Fisher and Reynolds had died, many of Lourd’s Scream Queens costars reached out via social media to send their support. Read the touching messages from Jamie Lee Curtis, Ariana Grande, and more here.