Billie Eilish is mourning the death of her beloved childhood dog.

The 'Ocean Eyes' singer has paid a touching tribute to her "sweet girl" Pepper and shared a series of pictures of her canine companion, including one of the Grammy winner with tears rolling down her eyes while hugging the pooch.

Billie captioned the Instagram post: "pepper. my life long best friend. i will see you again someday sweet girl. you made it 15 years you f***ing beast. i love you. rest easy mama, i’ll miss you forever. this is a really hard day (sic)."

Alongside another photo on her Instagram Story, she added: “Goodbye my angel.”

Animal lover Billie also has a Pitbull called Shark

The 'when the party's over' hitmaker celebrated his first birthday in 2021, and admitted he makes her life "1,000 times better".

Taking to Instagram, she gushed at the time: "my sweet rescue baby boy was born a year ago today ... you have made my life 1000x better happy birfday little shark ... (and if you’re thinking about fostering or adopting ... this is your sign) (sic)"

Meanwhile, Billie recently revealed she used to play with her Barbies to express her personality growing up.

The 21-year-old pop star has written and released the track 'What Was I Made For?' with her brother Finneas for the soundtrack of Greta Gerwig's blockbuster 'Barbie' and explained that playing with the iconic Mattel doll was a huge part of her childhood and she thinks that the character is a way of representing everyone.

Speaking to Zane Lowe on Apple Music 1, she said: "Oh gosh. Well, Barbie was my childhood. Truly, Barbie was my every day as a kid. It's a beautiful doll, please. She's everything, too. She's everyone. There's so many Barbies and there's so many different versions and different… all my Barbies had their own personalities and opinions and thoughts, and styles and ideas of the world. And I was just a little kid talking for them, but they still had the personality to me."