Billie Eilish Mourns the Death of 'Life Long Best Friend' Dog Pepper in Heartbreaking Post

Billie Eilish bid farewell to her childhood friend this weekend. Pepper was a black and white dog with a distinct spot over her eye. The "lovely" singer is an animal activist and a dedicated vegan.

"Pepper. my lifelong best friend, " Billie Eilish wrote late on Sunday. "I will see you again someday, sweet girl. You made it 15 years, you [expletive] beast. :’) I love you. Rest easy mama I'll miss you forever. This is a really hard day."

The Grammy winner shared photos of Pepper as a puppy, of her cuddling the dog in her early teens, and a photo used as a New Year's message from a few years ago with her family, all with spots painted over their eyes like Pepper.

At the start of the COVID-19 pandemic, the star used the downtime in her schedule to foster two puppies. She said on a podcast that the experience had been "amazing and a full-time job at the same time," adding, "I feel like more people should [foster puppies].

In mid-April 2020, the singer shared on her Instagram stories that she adopted one of the puppies and the other one "got a different forever home!!"

People for the Ethical Treatment of Animals (PETA) recognized Billie Eilish for promoting veganism and animal causes by naming her their 2021 Person of the Year. It is an honor bestowed on celebrities like Oprah Winfrey and Joaquin Phoenix in previous years.

At the "Power Our Planet: Live in Paris" concert in June, Billie Eilish said that the most important thing to do about climate change is to adopt a more plant-based diet to end animal agriculture. The singer has followed a vegan diet since she was 12.

She released the music video for "What Was I Made For?" from the "Barbie: The Movie" soundtrack on July 13. Her brother and collaborator FINNEAS called it one of his "favorite writing experiences ever" and sent love to the movie's director Greta Gerwig.