Billie Lourd has paid tribute to her late grandmother Debbie Reynolds on her 86th birthday.

Debbie Reynolds and Billie Lourd (c) Instagram

Debbie Reynolds and Billie Lourd (c) Instagram

The 25-year-old actress has taken to Instagram to post a picture of her late grandmother - who tragically passed away the day after Billie's mother Carrie Fisher died in December 2016 - on what would have been her 86th birthday.

The picture shows Billie, Debbie and her dog Dwight, and the caption was a series of emojis including crowns, stars and a love heart.

Carrie - who is best known for her role as Princess Leia in 'Star Wars' - was recently awarded a Grammy for her audio-recording of her 2016 memoir 'The Princess Diarist' and Billie admitted on the social media site how "proud" she is.

Alongside a picture of her with her mother, Billie wrote: "Princess Diarist was the last profesh(ish) thing my momby and I got to do together.

"I wish she was here to carry me down the red carpet in some bizarre floral ensemble but instead we'll celebrate in true Carrie style: in bed in front of the TV over cold Coca Colas and warm e cigs.

"I'm beyond proud. (sic)"

'Scream Queens' actress Billie recently revealed she is finding the death of her mother, as well as her grandmother, "impossible to deal with".

She said: "Yeah, it's completely surreal. There's no way to really explain it. It's so hard to talk about. I don't know, if I say that I'm doing good, I'm too happy.

"And if I say that I'm not doing good, then I'm a mess. So it's really hard to know what to say about it because it is just so surreal and impossible to deal with."

Meanwhile, Carrie's brother Todd previously praised his niece for staying strong in the wake of the family's terrible losses.

He said: "She's dealing with two gigantic losses. These two girls - my girls, my mother and my sister, were big, big personalities [with a] big influence on Billie, myself, many people.

"There's a vacuum in the room and she's feeling it and we're all feeling it. It's just that I'm 59 and I have no choice but to step up and put this stuff forward.

"I'm letting [Billie] breathe, you know? She needs to breathe. She needs to step back from all of this loss."