(CNN) -- Billie Lourd thanked her supporters Monday for giving her "strength" while dealing with the deaths of her mother, Carrie Fisher, and her grandmother, Debbie Reynolds.

The 24-year-old took to Instagram with a heartfelt message, along with an old picture.

"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. There are no words to express how much I will miss my Abadaba and my one and only Momby. Your love and support means the world to me."

Lourd had not released a statement since Fisher and Reynolds died last week.

The family is reportedly planning a joint funeral for the actresses. No date has been announced.